In this chapter, we present a literature review ordered as a history of the development of theories on migration and religion, addressing the main works on migration to Europe, adding the influential perspectives developed in relation to migration to North America. As a literature review, it is written in a denser style than the rest of the book; therefore, we end each section with a short summary.

1 Early Research (1903–1970s)

Already from the early twentieth century, research on contemporary international migration has commented on religion, not least studies from the USA. Introducing early American immigration (slave-)history, the work by William E. B. Du Bois on African American churches in the US – principally his book The Negro Church (1903) – is generally considered the first sociological or social science research on migration and religion (see also Woodson, 1921). Du Bois primarily emphasises the religious affiliation of African Americans during this period as social, and only secondarily as religious. Belonging to these religious communities strengthened African Americans in the fight for rights but it was not religion as beliefs and rituals that led to resistance. Instead, he argues, that it was foremost the social aspects of the congregations that supported the political work for equality. That attentiveness to the social aspects of religious engagement became a typical trait in later studies.

Another example of early immigration research including religion is William Thomas and Florian Znaniecki’s (1996) ground-breaking sociological book, The Polish Peasant in Europe and America, originally published 1918–1920. Based on life histories, diaries and letters sent between Polish settlers in the US and relatives in Poland, the authors demonstrate how the religious function that parishes had in Poland also was of great importance in the US. However, in the US the parishes came to have more functions – especially social – a change in function of religious organisations due to migration seen in many later studies (see also Harkness, 1921).

Published 10 years later, Richard Niebuhr’s book, The Social Sources of Denominationalism (1929), describes how Christian denominations in the US can be better understood by focusing on economic, social, racial and political differences, instead of differences in theology or ritual. In one of the chapters, he scrutinises what he calls the churches of the immigrants, claiming that these go through two important processes: a process of accommodation when they become more and more like the already established denominations, and a process of differentiation due to their need to distinguish themselves from other denominations. Both these processes were related to the US context which was, and still is, characterised by competition between the various denominations and the mobility of adherents. To be able to compete, the immigrant churches had to be both recognisable and unique. These two processes, Niebuhr claims, included a shift towards revivalism to attract members, while altered relations between the churches and the state tended to depoliticise immigrant churches. A third change has to do with the language used during sermons or other religious practices: English – which for the second and third generations was the only one they fully understood (accommodation) – or the former mother tongue, bringing with it emotional and nostalgic remembrance (differentiation)? It should be pointed out – as the book does – that the other denominations in the US, established during the 18th and 19th centuries, were also founded by immigrants.

Another early contribution to religion and migration research is The Religious Aspects of Swedish Immigration: A Study of Immigrant Churches (Stephenson, 1932). In the study, Stephenson describes how immigrants from Sweden go through changes in religiosity and establish, or join, churches in the US. He also shows the importance of the repatriation, or rather circular migration, to Sweden, leading to the establishment of new churches in Sweden at the end of the nineteenth century and the beginnings of the 20th. He is likely the first to affirm the importance of migration for the development of religion in the sending countries (see also Wolf, 1947).

The Yankee City study from 1930 to 1935 headed by William Lloyd Warner, which resulted in five volumes (Warner, 1959; Warner & Lunt, 1941, 1942; Warner & Srole, 1945; Warner & Low, 1947), is also worth mentioning. The project studied the settlement of ethnic groups and the various social factors in Yankee City, a fictive name for a town in Massachusetts. This study did not focus on religion, yet it clearly shows that religion had an influential role in the social constructions of ethnic groups. Supporting this conclusion, Warner and Srole (1945) demonstrate that religious structures are the first social structures to be formalised after arrival and also those that most strongly preserve the ethnic group. At the same time, they may hinder assimilation. The authors further stress the importance of understanding how the status of religion in the former home country connects with its role in the country of immigration.

Oscar Handlin’s historical exposition about immigrants to the US, The Uprooted (1951), is another good example of an early study addressing religion. He highlights the importance of religion to the studied people and how it supports integration, and demonstrates that religious denominations adapt to the situation of increasing immigration and end up competing. He further observes that the lack of established leadership created a culture of volunteering and contributing. Handlin is one of the first to notice the transnational aspects of religion; for these immigrants, religion fills an important function when nurturing relations with countries of origin.

Will Herberg’s Protestant – Catholic – Jew (1955) focuses on how religion is re-created and changed in the US because of migration. Like Du Bois, he argues that a common feature of the title’s three religious denominations is that affiliation to them is less about theological than social belongingness, which was of fundamental importance to ‘the American way of life’ and to becoming an American. Both Handling’s and Herberg’s studies claim that migration causes losses and difficulties, and that religion plays a crucial role in the establishment of migrants in the new country by providing meaning and group affiliation.

Religion also plays a role in Nathan Glazer and Daniel Patrick Moynihan’s influential book on immigration and ethnicity in New York, Beyond the Melting Pot (1970 [1963]), in which they relate how, after arriving to New York, Puerto Ricans soon sought out other religious denominations than the Catholic Church, including various Pentecostal congregations. The main reason for this was that they could not identify with the Catholic Church that, at the time, was dominated by the Irish and had no Spanish-speaking priests. This observation stresses, yet again, that group identification was even more important than theology.

Milton Gordon’s Assimilation in American Life: The Role of Race, Religion, and National Origins (1964) has a similar aim as Beyond the Melting Pot. Yet it is broader in scope, with an ambition to say something about America. Gordon explores the social arenas based on ethnicity, religion, race and nationality where assimilation takes place, and constructs theories about assimilation processes. He further presents some empirical examples of these complex assimilation processes by analysing three religious groups (Jews, Catholics and white Protestants) and the African American community, describing how, over time, they have come into being through immigration, and how they relate to national and ethnic belongings. To make the reader aware of the many nuances in an overall assimilation process, Gordon separates between different forms of assimilation: for example, ‘identificational’, attitudinal, marital and structural assimilation. Someone may thus be assimilated in dress, behaviour and most attitudes but, in structural terms, primarily engage off-work with religious peers. This resonates with our earlier distinction between different types of integration (see Sect. 1.7).

The 1970s saw the emergence of new research on the organisations of Czech, Italian, Irish and Polish Catholic ethno-religious groups as well as Armenian Orthodox, Eastern-European Jewish and Buddhist. The anthology, Immigrants and Religion in Urban America (Miller & Marzik, 1977), provides various descriptive examples of the constructions of the foremost Catholic ethno-religious groups in urban America from the late nineteenth century until the 1970s, while Tetsuden Kashima (1977) gives an overview of Japanese Buddhists and their organisations in the US in the book Buddhism in America: The Social Organisation of an Ethnic Religious Institution. The author emphasises the ethnic and religious importance of these organisations for Japanese immigrants but foresees a broadening of ethnic groups joining the organisations, concluding, ‘If this occurs, Buddhism will indeed become fully Americanized’ (p. 220; about Buddhism from this period, see Laymen, 1976).

There are also some examples from the 1960s of European research. Johannis J. Mol’s book Churches and Immigrants: A Sociological Study of the Mutual Effect of Religion and Emigrant Adjustment (1961) is an attempt to collate European and US research on immigration that includes religion (i.e., Christianity and to some extent Judaism) and to sketch a theory – or rather a model. Mol innovatively includes religion on both an institutional and an individual level in his model while earlier research focuses on religious organisations. However, the empirical verifications for religiosity and the religious needs of the immigrants are vague and, to some extent, the book is theologically biased (Mol, 1961; see also Mol, 1959).

Two other examples of early European research are about West Indians in the UK and their religious belonging and organisation, both as Pentecostal groups and in relation to the majority churches (Calley, 1965; Hill, 1963). In these case studies, problems of integration into British society among West Indians in the UK, not least with the majority churches (such as the Church of England and other non-Pentecostal churches), are seen as explanations for opting out of the latter and joining Pentecostal groups and for the turbulence in the studied West Indian Pentecostal congregations.

A similar study is Kenneth Pryce’s PhD thesis, Endless Pressure: Study of West Indian Life-styles in Bristol (1974). Pryce investigates how different social structures, called ‘life-styles’, among the West Indians in Bristol function in processes of adaptation. One important lifestyle is provided by the ‘all-black church’ of Pentecostal origin, to which many of them belong. The church – the author calls it a sect – provides a social context and a place in which their situation as working class and their experiences of racism can be put aside. Instead, they can take comfort in God and the coming of another world after this life. The church offers social help and provides a sense of community; however, it also offers them ethics and morals seen as desirable by the society from which they have withdrawn.

Hans Mol’s studies (1976, 1978, 1985) are based on statistical data, and show how international migration, primarily to Canada and Australia but also Belgium, France, Italy, Holland, the UK and the US, changes the religiosity of individuals. Mol describes the relevance of religion in immigrants’ identity constructions. Compared to other studies, these indicate a decline in religiosity among immigrants in the countries of immigration.

1.1 Summary

We already find some recurrent topics and trends in these early studies. First and foremost, they emphasise the importance of organised religions for identity and group belonging for immigrants. There is an increasing tendency for religious organisations to take on social network functions in new countries. For many, they become a home away from home. This is crucial for the immigrants’ perception of themselves and empowerment. At times, religious commitment is associated with lesser levels of social and cultural integration. When qualitative research is done in these organisations, the positive aspects of religion and religious engagement clearly dominate – religion and religious communities provide moral compasses – but through statistics, other patterns may surface, such as indications of religious decline. Finally, a few studies note that the experiences of migrants may also affect the countries of origin.

2 Scholarship in the 1980s and 1990s

2.1 American Scholarship

Most of the migration studies from the 1980s and 1990s that included religion relate to the US. Not many studies on the topic were published during the 1980s (see also Kivisto, 1992); however, we find some examples. There was a growing amount of research on the Muslim immigrant population in the US (e.g., Abu-Laban & Suleiman, 1989; Abraham & Abraham, 1983; Waugh et al., 1983) and immigrants with East Asian backgrounds (e.g., Fenton, 1988; Yu, 1988; Lewis, et al., 1988; Shin & Park, 1988; Williams, 1988), a trend that continued into the 1990s in the US (on Islam see, e.g., Haddad & Esposito, 1998; McCarus, 1994; Haddad, 1991; and on Asian religions see, e.g., Yang, 1998, 1999; Numrich, 1996; Rutledge, 1991).

A couple of books providing exceptions to this focus on Islam and Asian religions are about Catholicism in the US and its relations with immigration (e.g., Dolan, 1985; Hennesey, 1981). The American Catholic Experience (Dolan, 1985) presents the history of Catholicism in the US from the sixteenth century until 1980s. The author closely examines the emergence of what he from 1860 labels to be an immigrant church, and how this is related to ten different national immigrant groups (Czech, Italian, Irish and Polish, German, French Canadian, Mexican, Slovak, Lithuanian, and Ukrainian groups. The author claims that during the beginning of the twentieth century at least twenty-eight different nationalities were represented in the Catholic Church in the US leading to plurality and dynamics, but also to several problems that needed to be solved to keep the Church together (Dolan, 1985).

Raymond Williams’ Religions of Immigrants from India and Pakistan: New Threads in the American Tapestry (1988) is mostly about Islam and so-called ‘Asian religions’ (Buddhism, Hinduism, Jainism, Sikhism), but also includes minor parts on Christians, Jews and Zoroastrians. By choosing the countries of origin as the primary starting point, and not religion, Williams’ book is innovative in its approach to the study of religion and immigration. This encourages investigation of how former national contexts and the immigrants’ history in the chosen countries influence religious adaptation in the country of settlement, and also the impact of length of stay and local population size. Williams traces four patterns across these religions in processes of adaptation in the US, identifying what he calls an ecumenical pattern, a national pattern, an ethnic pattern and a sectarian pattern – the first being the most inclusive and the last the most restrictive in terms of contacts with others. Regardless of degrees of interaction with the surrounding society, Williams foresees many common problems in holding immigrant religious groups together over time, among them those caused by people’s geographical mobility and the difficulties of generating new leadership, maintaining language competence and transmitting religious traditions.

From the mid-1990s, we see an overall increase of studies in the field as it became established as a subfield within migration research (which was also an expanding field at the time). The growing amount of research in the US, including various larger research projects, was accompanied by more theoretical outcomes. Further, such work dealt not only with specific religious traditions, but also topics such as transnationalism and globalisation. One early example of these research projects is the Pluralism Project at Harvard University, which started in 1991 under the direction of Diana Eck and is still ongoing (Eck, 1997, 2001, see also https://pluralism.org/). Its aim has been to map, investigate and understand the religious landscape emerging in the US after the Immigration and Nationality Act of 1965.

The New Ethnic and Immigrant Congregations Project (University of Illinois, Chicago, 1993–1997) was another US-based, influential research project from the period. A product of the project, Stephen Warner and Judith Wittner (1998), Gatherings in Diaspora: Religious Communities and the New Immigration, incorporates studies of ten different immigrant congregations (including Christian, Muslim, Hindu, Jewish and Rastafarian) in different parts of the US, and shows a broad spectrum of how and why they come into being and how they are upheld. The project recruited researchers who had ‘linguistic, religious, or national-origin’ in common with each studied group, with the goal of gaining access in ways it was believed would not have otherwise been offered (Warner, 2000: 270). The project brought to the fore features including aspects of identity formation, the reception of new immigrants into the established congregations (‘proximal hosts’), congregational adaptation and how congregational differences (gender, generation, cohort) are handled. One of the crucial conclusions from this project was that immigrant congregations tended to adapt, over time, to the institutional forms of Protestant Churches.

This assumption, among many other things, was tested and verified in another large US research project of the 1990s, The Religion, Ethnicity and New Immigrant Research Project (1996–99), headed by Helen Rose Ebaugh and Janet Chafetz (Ebaugh & Chafetz, 1999, 2000, 2002; Ebaugh et al., 2001; Yang & Ebaugh, 2001a, b). The project examined thirteen immigrant congregations in the same city (Houston, Texas), using formalised interview guides and observation protocols to facilitate comparison between them. The findings were that gender roles were both upheld and transformed (equalised) and that formal and informal religious structures together provided social services to the immigrants. Further, researchers stressed the importance of majority or minority positions in both the US and the former homelands for congregational strategies and activities. Ebaugh and Yang conclude that three principal processes of change are typical of these congregations:

  1. 1.

    that they are adopting the congregational form in organisational structure and ritual,

  2. 2.

    they are returning to theological foundations as they confront diverse sub-traditions and ethnic groups within a religion; and

  3. 3.

    they are reaching beyond traditional ethnic and religious boundaries to include other peoples. (Ebaugh, 2010: 107)

To study transnational ties, a follow up project – The Impact of Transnational Religious Communities on Immigrant Incorporation in the United States, (1999–2002) – was launched in which in-depth studies were made of six of the congregations using network analysis. The researchers examined how so-called social remittances of religious items were transferred between individuals with ties to both the sending and receiving countries. They also investigated how practiced religions changed, not only in the US, but also in the country of origin (Yang & Ebaugh, 2001a, b; Hagan & Ebaugh, 2003; for ‘social remittances’ see Sect. 3.4). Another US research project of the period investigated religious diversity in Atlanta, headed by Gary Laderman (1996).

About this time, Stephen Warner (2000) drew together lessons learnt from the large US-based projects into general principles: (1) Religion is typically salient for migrants; (2) migration is not random with respect to religion; (3) identities – individual and collective – are not primordial but negotiated; (4) Religion in the US is subject to processes of isomorphism – that is, taking on the same form – toward congregationalism; (5) congregations (and other religious institutions) become vehicles or venues of intragroup dynamics. While the first principal can be taken for granted in the context of this book, the second is interesting, as Warner sees religious persecution as an important push factor. He points out that while many migrants come from the Middle East, the numbers of Jews, Bahai and Christians are disproportionately high. Points 3–5 will be discussed in Part Two of the book; here it is enough to stress the role of religion in relation to identity negotiations. Warner further demonstrates that organised religion takes on the forms common in the country of immigration and that such organisations also become sites of negotiations, not only of personal identity.

About this time, other US studies with a transnational focus on religion began to appear. Peggy Levitt is an influential scholar who has presented ideas on how religious expression moves back and forth between the countries of origin and the country of immigration (1998, 1999, 2001). Her book, The Transnational Villagers (2001), which is based on in-depth fieldwork among immigrants from Miraflores in the Dominican Republic, describes their religious life in both Boston and Miraflores. She also highlights religious organisations as an important intermediary area where bridges are built between the individual and social institutions, and social interaction takes place.

Transnationalism is further developed in Levitt’s God Needs No Passport (2007). The study uses large data sets drawn from members of four immigrant religious groups in Boston – Pakistani Muslims, Gujarati Hindu organisations, Irish Catholics and Brazilian Evangelical Protestants – which demonstrate the important role played by religious organisations in their transnational lives (see also Rudolph & Piscatori, 1997).

During this period, US research on religion and migration, just like general migration studies, came to embrace processes of globalisation, including the diaspora concept (e.g., Roy, 2004; Rukmani, 1999; Cohen, 1997).

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In sum, the sparse US research on migration up until the 1990s was mostly concerned with religious communities and how these could help or hinder migrants in adapting to new societies. There was particular interest in Muslim groups, but also some studies on Catholicism. The focus was largely on history and the success or failure of organisations. It was common for researchers to stress that immigrant religious organisations accept forms that are dominant in the new country and take on new social roles.

During the 1990s we see an increase in well-financed, large research programmes, leading to the establishment of migration and religion as a subfield within migration research. Research came to include more comparative and theoretical studies of congregations, allowing for critical observations on gender and generation. Transnational migration – focusing on the relationship between the receiving society and the migrants’ homeland communities – along with globalisation processes and diasporas, also appeared on the research agenda. Studies demonstrated that, in many ways, religions and religious identities are and have been non-territorial, flexible and elastic, and often very important and durable, compared to other social identities.

2.2 European Scholarship

To some extent, European migration researchers started to include religion systematically in the 1980s, increasing rapidly in the 1990s, most of which focused on Islam and Muslim immigrants (e.g., Nielsen, 1998; Vertovec & Rogers, 1998; Nonneman et al., 1997; Vertovec & Peach, 1997; Geaves, 1996; Schiffauer, 1991; Shadid & van Koningsveld, 1991). Frank Buijs and Jan Rath (2006: 5) estimate that more than a thousand publications on Muslims in contemporary Europe were written before the beginning of the 2000s, and a vast majority of these are from the 1990s.

The few studies that preceded them were largely produced by scholars writing in French and researching the Muslims of France in the 1980s (e.g., Kepel, 1987; Krieger-Krynicki, 1985), along with a number of pioneering UK publications (e.g., Nielsen, 1981; Anwar, 1980). Some groundbreaking studies of Muslims in Europe can be found in the Journal of Muslim Minority Affairs launched in 1979, most of which are descriptive, focusing on the history of a particular religious denomination. Information about religion can also be found in studies on immigrants with Muslim backgrounds, especially in the ethnographic literature on Turkish immigrants in Germany, Netherlands and Sweden from the 1970s and onward (e.g., Sachs, 1983; Waardenburg, 1983; Elsas, 1983).

One of the first influential and widely disseminated publications on Muslims in Europe is The New Islamic Presence in Western Europe, first published in 1988 (Gerholm & Lithmann, 1990). The edited book gathers together the leading researchers of the time, covering among other things the institutionalisation of Muslim interests and detailing the development of Qur’an schools, organisations and networks. In it, sociologist John Rex, one of the pioneers of UK immigration research, theorises about immigration, ethnicity and religion, seeing religion not as a subcategory of ethnicity but as an intriguing phenomenon interlaced with ethnicity. He is one of the first to do so.

During the late 1980s and 1990s, the publications on migration, Islam and Muslims addressed various areas such as leadership (e.g., Moreras, 1999), integration (e.g., Shadid & van Koningsveld, 1991), youth (e.g., Vertovec & Rogers, 1998; Jacobson, 1998), globalisation (e.g., Alsayyad & Castells, 1997), education (e.g., Anwar, 1988), law (e.g., Shadid & van Koningsveld, 1995), and space making (e.g., Metcalf, 1996). In the 1990s, research on Islam and Muslim immigrants in Europe primarily paid attention to matters connected with political science, such as integration, institutionalisation, laws, democracy, diversity and multiculturalism and secularity, and, only to a lesser degree, to religion-related topics such as theology, faith, rituals, identity building and traditions among Muslim immigrants.

A substantial trend in European research on Muslims during this period examined authority and individualisation, developing theoretical perspectives that addressed how individual integration processes are intertwined with a renegotiation of the locus of authority (e.g., Peter, 2006; Buijs & Rath, 2006). The argument behind this is that the lack of strong socialising institutions in non-Muslim majority countries force or enable (depending on perspective) Muslim migrants to formulate Islam more freely. This line of inquiry was to form a strong paradigm within research, one still present in the literature from the 2000s and 2010s (e.g., Roy, 2004; Tietze, 2001). However, from 2000 onwards research has, according to Frank Peter (2006), come to include more studies on representatives of Muslim authority, such as imams, preachers and muftis, when explaining the ongoing changes in Muslim communities.

There was some research into other religions, but it was rather sparse; for example, settlements in Europe are included in the US books mentioned above with a globalisation and diaspora perspective (e.g., Cohen, 1997; Rukmani, 1999). During this period, there were publications about, or that included the investigation of, Christian communities in Britain established by immigrants from African countries and the Caribbean (e.g., Kalilombe, 1997; Weller, 1994; Ward, 1989; Howard, 1987) and about Hindus in Britain and the Netherlands (e.g., Shadid & van Koningsveld, 1991). Religion and Ethnicity: Minorities and Social Change in the Metropolis (Barot, 1993), with chapters on immigrants and religion in urban settings in the UK, Sweden and the Netherlands, is an early example of an anthology which centres on religion, migration and the city, a theme that becomes more common in the 2010s. Four years later, the book Transnational Religion and Fading States (Rudolph & Piscatori, 1997) was published, which contains a chapter on the Catholic Church as a transnational institution.

The literature on migration, Jews and Judaism is rich and, while largely focused on Jewish migration within Europe, to North America or to Israel (e.g., Lewin-Epstein et al., 1997; Goldstein & Goldstein ,1996), it holds many theoretical ideas on subject formation in modernity and postmodernity, community building, diaspora, transnationalism and globalisation. A fine example is Jewish Identities in the New Europe (1994) edited by Jonathan Webber. In it, Webber discusses identifications with national and Jewish identities, especially how the Jewish identity, once a given, is today more fluid, open and up to the individual, while national identities now tend to be seen as given. Subjects such as the authority of rabbis and antisemitism are also addressed in the book.

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Thus, what separated US and European research at the time was the stronger focus on Islam and Muslim immigrants in the latter. Starting in the 1980s, research on Muslims immigrants really took off in the 1990s, while some researchers were also paying attention to other religious groups. As with the US research, much of the initial focus was on organisations and established religious environments, their history and social functions. Later, topics became broader and, not least, theories on religious authority versus individual autonomy were developed. In hindsight, research questions were often formulated from the concerns of the established in society, and discussed issues connected with integration and multiculturalism.

3 European Scholarship from 2000–2010

There was an increase in the amount of research published during the period from 2000 to 2010, with a growing input from Canadian scholars (e.g., Beaman & Beyer, 2008; Bramadat & Seljak, 2005; McLellan, 2004) – too voluminous to be presented here. Instead, with a focus on Europe, we mention some examples of different topics that continued from the 1990s and new areas that appeared.

Research on Islam and Muslim immigrants in Europe dominated academic work on religion and migration during this period, and included areas from the decade before, such as leadership (e.g., Kroissenbrunner, 2001; Schiffauer, 2000), integration (e.g., Martín Muñoz et al., 2003; Maréchal et al., 2003), youth and the second generation (e.g., Jacobsen, 2006; Tietze, 2001) and law (e.g., Cesari, 2010, Roald, 2009). We can also observe the growth of research conscious of gender theory (e.g., Farahani, 2007; Keaton, 2006) and the development of new Islamic ideas (e.g., Otterbeck, 2000; Nielsen, 1999). However, a rather large proportion of research on Muslim immigrants maintained a political science focus, while adding an increasingly politicised angle. Themes such as governance (e.g., Bramadat & Koenig, 2009; Bader, 2007), democracy and law (e.g., Sayed, 2009; Cesari, 2004), multiculturalism and diversity (e.g., Al-Azmeh & Fokes, 2007; Bader, 2003), radicalisation (e.g., Kühle & Lindekilde, 2010; Neumann, 2009), securitisation (e.g., Kaya, 2009) and Islamophobia (e.g., Allen, 2010; Otterbeck & Bevelander, 2006) exemplify this trend. This led to more polarised research, and research results were frequently both presented and read through a political lens.

Research into religions other than Islam in connection with migration was also becoming more common, producing works on Europe and Buddhism and Buddhists (e.g., Prebish & Baumann, 2002; Baumann, 2000), Christianity and Christians (e.g., Ter Haar, 2008; Roudometof et al., 2006), Hinduism and Hindus (e.g., Jacobsen & Kumar, 2004; Baumann, 2000) and Sikhism and Sikhs (e.g., Singh & Tatla, 2006; Hall, 2002). Books were also published on European Jews and Judaism, but if they touched on migration, it was generally intra-European. These studies are mostly about religious organisations and their relations with the receiving countries in Europe and less about themes such as the organisations’ religious traditions or religiosity among their adherents or among immigrants not belonging to religious organisations or majority churches.

Meanwhile, there were two fields that were expanding: comparisons between the situation in the US and Europe (e.g., Chebel d’Appollonia & Reich, 2008; Foner & Alba, 2008; Coward et al., 2000) and the trend in US research from transnational studies to studies with a more global focus; the latter was also possible to relate to the European context, as Europe is part of these processes (e.g., Roudometof et al., 2006; Prebish & Baumann, 2002). Those themes found in research on Islam and Muslims in Europe can also be found in work on other religions and religion in a more general sense, but to a lesser extent. There are publications from the period about authority and leadership (e.g., Währisch-Oblau, 2009), integration and diaspora (e.g., Vertovec, 2000; Coward et al., 2000), youth (e.g., Berry et al., 2006), and gender and generations (e.g., Singh & Tatla, 2006; Cetrez, 2011), but also about specific cities (e.g., Martikainen, 2004). Unfortunately, there is very little research from a political science perspective relating to religions other than Islam touching on subjects such as governance, democracy, multiculturalism and diversity, radicalisation and securitisation. We must keep in mind that the socio-political situations of Muslims – giving due weighting to postcolonial resistance, political Islamism and jihadi extremism – are historically specific, but research on other politicised religious identities and migration would be beneficial, particularly for comparative reasons. While there are a few studies, such as an analysis of Hindutva identity among UK Hindi students (e.g., Raj, 2000), they rarely connect results to migration (for exceptions see Bramadat & Koenig, 2009; Bader, 2003). We also find that the early interest in US research on the importance of religion to immigrants’ lives is evident in European studies during the 2000s (e.g., Otterbeck, 2010; Nordin, 2004).

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Thus, while there was still a clear focus on Muslims, there was also a growing interest in people of other faiths and an increased diversification of perspectives. Rather than making its own theoretical contribution, religion and migration research was increasingly relating to the theories that were already in circulation, with both positive and negative effects. While it connected such research to broader theoretical developments in the social sciences, it also reduced the focus on religious studies questions. All this was also typical of the following decade.

4 European and Some American Scholarship from 2010

The number of publications by this period was incalculable, and we start to find book-length, comprehensive overviews of the phenomenon in general (e.g., Ramji & Marshall, 2022; Kivisto, 2014; Connor, 2014; Breton, 2012). There was also a rise in the number of publications written from European perspectives. The presentation below mainly addresses these or publications that include Europe, and only overarching themes are discussed.

A growing number of anthologies were published with themes such as the city (e.g., Goodhew & Cooper, 2019; Berking et al., 2018; Garbin & Strhan, 2017; Becci et al., 2011), which until then had been a somewhat neglected area in migration and religion research. This is surprising, since it is well known that immigrant communities often form in cities, and that immigration to western Europe includes people with higher levels of religious practice than that of the urban population in general. Other areas covered by the anthologies are globalisation (e.g., Cherry & Ebaugh, 2014), gender (e.g., Bonifacio & Angeles, 2010), age (primarily youth) (e.g., Sedgwick, 2015), geographical areas in Europe (e.g., Sideri & Roupakia, 2017; Vilança et al., 2014), integration (e.g., Burchardt & Michalowski, 2015), religious diversity (e.g., Hennekam et al., 2018) and securitisation (e.g., Cesari, 2010). Many but not all of these focus on Islam.

It is not until this decade that we start to see a larger number of studies about religious groups other than Muslims: for example, Buddhists (e.g., Swe, 2013; Borup, 2011), Christians, including a growing number of publications on charismatic/Pentecostal groups (e.g., Nilsson DeHanas, 2016; Kubai, 2014; Burgess, 2011; Knibbe, 2011), Orthodox churches (e.g., Sparre & Galal Paulsen, 2018; Hämmerli & Mucha, 2014), Catholics (e.g., Borup, 2011; Trzebiatowska, 2010), Hindus (e.g., Jacobsen & Sardella, 2020; Broo, 2010), Jews (e.g., Toffell, 2013; Goldin et al., 2019) and Sikhs (e.g., Singh, 2022; Jacobsen & Myrvold, 2011, 2012).

The research on Islam and Muslims was increasingly complemented by new themes. Most important among these was a new focus on creativity among migrants, stressing agency and political consciousness (e.g., Jouili, 2015; Lewis, 2015), everyday lived Islam among migrants (e.g., Toğuşlu, 2015; Dessing et al., 2013), LGBTQI+ individuals and groups pragmatically addressing the role of marginal sexualities in migration (e.g., Tschalaer, 2019; Peumans, 2018), detailed studies of radical organisation and thought (e.g., Inge, 2017; Nesser, 2015), the history of Muslim minorities – the Ahmadiyyas (e.g., Balzani, 2020; Jonker, 2016), the Alevis (e.g., Özkul & Markussen, 2022) and the Ismailis (e.g., Magout, 2020), early migration history in various countries (e.g., Sorgenfrei, 2018), discussion of minority law (e.g., Bowen, 2016), Islamophobia, complemented by whiteness and the racialisation of Muslims (e.g., Jakku, 2018) and, finally, the development of new Islamic ideas (e.g., Hashas, 2019; van Bruinessen & Allievi, 2011).

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As in former periods, there was a considerable emphasis on religion in relation to other social structures, and less on changes in religious organisations and religious practices, with some exceptions (e.g., Soeffner & Zifonun, 2016; Jeldtoft, 2012), discussed further in Part Three. Islam was still in focus and, although mostly regarded from a more political perspective, some other new areas were included. We also see a growing research interest in other religions and a marked rise in interest in the very formulation of religion and in rituals. The focus on cities and local environments also produced an awareness of the great relevance of socio-economic conditions in neighbourhoods, cities and regions to how immigrants formulate and express religion. Of the utmost importance is the new awareness of, and stress placed on, the complexities of religion to migrants in different subject positions.

5 Concluding Remarks

Research on migration and religion has been multidisciplinary, taking place in sociology, anthropology and history of religions; increasingly, however, it has become important in political science, with interest in topics such as the relations between secular states and immigration, and multiculturalism and religion. Religion and migration have been linked to law – when, for example, increasingly pluralistic and global societies challenge, among other things, religious freedom laws, demonstrating how laws are not universal but formed by local contexts and the historical dominance of particular forms of Christianity – and are studied by scholars of legal studies, while religion is also linked to migration in psychology, in trans-generational research and in studies of the role religion can play in traumas that can follow from living in refugeeship.

Even though research on migration and religion has grown during the last decades, it has still a quite limited impact within migration research in and about Europe. For example, there were no sessions at the 2021 IMISCOE (Immigration Migration Research Network) conference with religion as a topic, and out of more than 1000 papers, only 26 included ‘religion’ (or words related to religion) in the titles; at the 2020 IMISCOE conference a single session out of more than 100 sessions was about religion (see also Ebaugh, 2010). We hope partly to overcome this peripheral position of migration and religion with this book.

As we can see from the above discussion, research on migration and religion is complex and covers a broad gamut of phenomena. Would it not, then, be possible to present an overall theory on migration and religion? We argue that doing so risks missing crucial aspects of relations between them. Instead, in the following, we discuss how to understand religion in relation to migration, providing various examples of research done in accordance with this, delimiting the research done to post WWII and immigration to Europe.