Western Europe on the eve of the Reformation was, to a large extent, united by a single religion. Orthodox Christianity dominated the east and large areas of the Balkans were Moslem, but western Europe was Roman Catholic, and all subjects and sovereigns, at least outwardly, conformed to Catholic ritual.
All this would change after Martin Luther, a strong-willed German monk, nailed his 95 Theses to the church door in Wittenberg. This act didn't herald the birth of a fully-formed Protestantism but, over time, a critical mass of German princes and commoners would come to endorse his critiques and a series of distinctive Protestant faiths emerged. The term 'Protestant' was first used in 1529 when several German cities and states protested against the Imperial Diet's decision to cancel the toleration formerly enjoyed by Luther's adherents.
Luther's critique of medieval Catholicism did not fall on stony ground for the Catholic church's theological hegemony had always been more apparent than real. English Lollards, Moravian Hussites and French Cathars had challenged aspects of Catholic practice and ritual, and when Luther's critique of medieval Catholicism blended with this legacy of dissent and the enquiring mindset of Renaissance Humanism, the stage was set for a religious revolution.
Map 2 reveals the spread of Protestantism in the decades following Luther's revolt. The Reformation was primarily a northern European phenomenon. England broke with Rome in 1534 when Henry VIII declared himself Supreme Head of the English national church, and Scotland declared itself Protestant following a revolt against the Guisian Regency in 1560. Ireland remained overwhelmingly Roman Catholic throughout this period, and when Protestantism reared its head in Italy and Spain, it was quickly suppressed.
As a nation which straddles both the northern and southern halves of Europe, France was convulsed by a series of debilitating Wars of Religion between 1562- 1598. These Wars of Religion reached an apogee in 1573 when 20,000 French Protestants (Huguenots) were murdered by their political and religious opponents in the St. Bartholomew's Massacre. Prior to this, many Protestants had regarded the Catholic Church as misguided; after 1573, they viewed it as irredeemably evil. This act of barbarism also horrified many moderate Catholics.
The French Wars of Religion continued until 1598 when Henry IV (a Huguenot who had converted to Catholicism) proclaimed the Edict of Nantes, giving Huguenots the right to worship publicly, hold public office, administer their own towns and enter schools and universities. Louis XIV's Revocation of this Edict in 1685 sent shock waves throughout Protestant Europe and helped colour Scottish and English perceptions of James VII/II.
Maps 2 and 3 provide general overviews of Europe's religious balance of power, but do not acknowledge the subject's full complexity. Throughout this era, Catholics continued to worship in many Protestant states, while Protestants observed their faith in officially Catholic nations but this is not always indicated. Calvinism gained many adherents in the Netherlands and Rhenish Palatinate during the latter part of the century, and this is acknowledged in Map 3.
Map 3 reveals the consolidation of Protestantism in the ninety years following Luther's revolt, and the differentiation of Protestantism into a series of reformed faiths. Scotland and the Netherlands were Calvinist, Lutheranism dominated Scandinavia, north Germany and the Baltic states, and England embraced a moderate Anglicanism, though owing more to Calvin than to Luther. Charles I's attempt to enforce Anglicanism on the Calvinist Church of Scotland provided the spark which ultimately ignited the whole Civil War conflict. In 1618, large parts of Europe would become embroiled in a political and religious conflict which, because of its duration, became known as the Thirty Years War