For scholars of Western intellectual history, the fact that Arabic authors were bestsellers in an earlier age is well known. Today, however, when Islam is more visible on the world stage than ever, when some contemporary authors, with absolutely no evidence, label any discussion about Arabic influence on Western thought during the Middle Ages and Renaissance as “a mere gesture of political correctness”—the book under review is most welcome. Through careful study of the printed sources—thanks to the Renaissance technology of printing there is much material to work with—Hasse shows incontestably the massive influence of Arabic thinkers on the Medieval and Renaissance West, as well as the efforts of some Westerners at that time to deny and erase that influence, preferring a narrative that directly connected them with Greco-Roman antiquity. During the Renaissance the West began to self-consciously distinguish itself from its Arabic roots. Those famous Arabic authors who were once known to every European student were forgotten, no longer a “part of Western cultural memory.” Because these efforts to erase and forget have mostly succeeded, as witnessed by the widespread ignorance of these facts, and there is significant prejudice against Islam today, the present book is especially needed.

There was a new wave of translations into Latin, from Arabic and Hebrew, which began c.1480 and lasted about 70 years. This cannot be understood as a mere continuation of medieval interest in Arabic authors, whose prior translation movement ended c.1300. These translations consisted of two major projects: (1) translating Averroes’s Aristotle commentaries into Latin, and (2) replacing the medical Latin of the Canon with more accurate and up-to-date translations.

The Renaissance battle lines were drawn between those who favored the influx of Arabic thought, on the one hand, and the humanists who wanted to erase its influence, on the other. The physician, Leonhart Fuchs (1501–1566), who considered the medieval Arabic influence on Latin to have been corrupting, contrasted the “pure and learned” Greeks with the “rancid and foul” Arabs. The typical humanist view, expressed by Girolamo Donzellini (1513–1587), was that the Greek sciences—especially medicine—when translated into Arabic, were shipwrecked, leaving the Latins, who got them from the Arabic, lost until they were rescued by those who resorted to pure Greek sources.

At the other end, Guillaume Postel (1510–1581), a French scholar who recognized the value of Arabic scientific research, contrasted the second-century Greek physician, Galen’s, prolixity, with the simple clarity of Avicenna: “What you can see lucidly and clearly explained in Avicenna on only one or two pages, Galen in his Asiatic manner hardly manages to comprise in five or six major volumes.” Postel was among many who highly praised the Arabic authors, and showed gratitude for what they had added to Western thought. As I myself have shown elsewhere (2012), some accretions to medicine that the humanists took as evidence of corruption were actually the accumulation of empirical data, which showed the vitality of the Arabic scientific tradition.

Hasse determines which Arabic authors were most influential during the Renaissance by examining the histories of printed editions, and the university curricula, which indicate that Arabic authors were considered worth studying until long after the Renaissance. The number of editions and authors was vast—forty-four Arabic authors were available before 1700, and Averroes, in over one hundred editions—much more popular than many Western medieval authors. The presence of Arabic authors in university curricula created much of the demand for these editions. Hasse provides a useful comprehensive list of all these Arabic authors available in Latin in Appendix. Because the Arabic influence was so great, covering several fields, Hasse selects three disciplines to consider in this book: medicine, philosophy, and astrology, each of which was either the locus of a heated battle, or, as with astrology, actually gained in popularity during this period.

As witness to the great popularity of Arabic treatises, readers demanded to know the life details of their authors. This inspired the production of biographies and intellectual histories of these authors, even though based on poor or nonexistent sources. These biographies were also an important means for promoting the Arabic sciences. Hasse masterfully surveys the contemporary biographies of three men, representing his three example disciplines: Avicenna, Averroes, and Albumasar. He shows how these biographies contributed to the emerging discipline of intellectual history, driven by the need to find a place for Arabic authors who were “pagan but non-classical” and did not fit well within the existing genres of biographies.

Medicine was dominated by Avicenna’s Canon, which in the Middle Ages and after was the main medical textbook at the universities—perhaps the most influential and important medical textbook ever—that continued to be used in some schools until the eighteenth century. Interest in it increased as philologists sought to establish a better Arabic text and produce more accurate translations than the medieval versions. Pharmacology took a hit from humanists who attempted to show that the Arabic tradition was filled with corruptions, and that the Greek Dioscurides gave a purer, more scientifically accurate description of medicinal plants. Ironically, in their attempts to return to a pure Greek botany, the humanists not only failed—because Arabic authors actually had advanced the empirical science of medicinal plants, but their attempts to suppress Arabic materia medica led to new discoveries. Interest in Arabic medicine resumed, once the scientific value of the Arabic tradition was realized.

Averroes was the pivotal figure in philosophy, whose popularity as the Great Commentator on Aristotle took a hit after late antique Greek commentators on Aristotle were discovered, whose views were given more authority, and with the increasing interest in reading Aristotle in Greek. Attempts were made to discredit the Arabic Aristotelian tradition as being faulty on three counts: translation, transmissions, and interpretation. Moreover, Averroes’s controversial doctrine that all mankind shared a single rational soul, which humanists blamed on poor Arabic translation of Aristotle, was deemed heretical by the Church, which exerted great pressure to eradicate it. However, that theory died out eventually only because alternatives for it were found in the Aristotelian tradition itself.

In astrology alone was the reception mostly smooth, indeed, Arabic astrologers actually grew in importance in Europe, as interest in astrology at all levels of society reached its apogee in the period between 1550 and 1650. Arabic authors were the nexus and conduit of several traditions, Greek, Persian, Indian, which they combined into a compelling and useful tool. Authors such as Albumasar were valued because they synthesized the astrological tradition with the rest of natural philosophy in a way that Greek authors like Ptolemy had not, while adding several new techniques, such as using the great conjunctions of Jupiter and Saturn to compose astrological histories of the world.

The posthumous publication of Pico della Mirandola’s Disputationes adversus astrologiam divinatricem (“Arguments Against Divinatory Astrology”) in 1496, which is a compilation of arguments against astrology, opened a debate over the validity of classical astrology, while also contributing to the debate over the Arabic legacy. While often mischaracterized by modern scholars as a straightforward and sustained attack against astrology that ultimately undermined that tradition in the West, it is actually a more complex and multilayered work that seems to be a rejection of astrology in general, while trying to purge astrology of the corrupting Arabic parts, in order to create a “humanist” astrology that returns to pure Ptolemaic precepts. For example, in some places Pico criticizes the Arabic tradition for deviating from Ptolemy, but in others he criticizes the Latins for their ignorance of Arabic and Hebrew sources. In still others, he criticizes Ptolemaic astrology while respecting Ptolemy the man.

On the basis of Hasse’s masterful survey, there can be no doubt that Arabic thinkers played a significant role in two formative periods of the West: the Middle Ages and the Renaissance. Specialists in medieval history or history of philosophy or science are well-acquainted with the essential and productive influence of Arabic authors on the development of several disciplines. For these, Hasse’s book will be a welcome corroboration of that understanding, by looking at its tail end. For the general educated reader, knowledge of the pivotal role that texts translated from Arabic played in the foundations of the modern world may be elusive or seem fantastic, or may be based on the often-exaggerated claims of popular histories. For these, Hasse’s book is a firm but gentle, masterfully argued and presented case for the reality of this influence, and why it should matter in the world of the twenty-first century. A recently published study by Alexander Bevilacqua has a similar approach to Hasse’s, but considers the involvement of European scholars with Arabic texts during the later Western Enlightenment. Bevilacqua shows how, in their quest to understand Islam—in many cases motivated by the desire to proselytize Muslims—European scholars brought back to Europe influential ideas from Arabic authors. A comparative study and evaluation of these two books and the influence of Arabic thought on European intellectual life during the two periods they, respectively, cover would be most welcome.