In the England, Scotland, Ireland and their colonies, throughout the sixteenth and seventeenth centuries, no intellectual system may have exercised greater structural or imaginative significance than the theology of John Calvin. In this context, the influence of Calvin’s ideas far outweighed the circulation of his published works, and the tradition of translating his publications into English, especially in the second half of the sixteenth century, continued as his ideas were received, adapted and disseminated in the distinctive and sometimes tumultuous religious environments of the Tudor and Stuart territories. These ideas took impressive hold. By the middle of the seventeenth century, Calvinist ideas had moved from the margins to the centre of the religious, cultural and political life of the three kingdoms, feeding into the outbreak of civil war and facilitating the revolution that in turn created the short-lived Cromwellian republic. Simultaneously, Calvinism began to variegate, as the Reformed theologies that circulated within and occasionally between the English, Scottish and Irish churches took on distinctive flavours, in reaction to which, and with the goal of uniting these divided Reformed churches, Calvinist theologians created some of the most important of the early modern confessions of faith. One of the longest of these, the Westminster Confession of Faith (1647), was intended to achieve, but never achieved, the doctrinal unity of the three established churches, though it remains a constitutional benchmark of Presbyterian denominations around the world. Despite some extraordinary achievements, Calvinist theology was in decline by the end of the seventeenth century, being defended by a shrinking number of clergy and adherents of established and dissenting churches, haunted by its association with political instability and constitutional chaos, and challenged by the presuppositions of the early Enlightenment and the emergence of trans-Atlantic evangelicalism as a variety of popular Protestantism better adapted to the religious circumstances of the early eighteenth century.