Three circumstances of the 1640s help explain the emergence of the Levellers and the survival of some of their radical political ideas for the next forty years. First, the city of London experienced phenomenal population growth throughout the seventeenth century. Leveller followers and successors were concentrated in the less structured neighbourhoods developing outside the city walls, where the new gathered churches of the more sectarian puritans also flourished. Secondly, the Levellers arose in response to the frustrations of the civil war of 1642–1647 and to popular political disillusionment with the parliamentary and civic leadership thereafter. Thirdly, the Levellers developed as a political faction in the midst of several revolutionary challenges to the pre-1642 religious, political, and social order: the expanding political press, sectarian rejection of clerical domination of religious life and thought, the rise of new commercial interests, and the restlessness of some artisans, apprentices, and urban women.