Reformation-Counter Reformation, the Christian Church at War with itself!
In 1517, Martin Luther wrote his Ninety-Five Theses, complaints on what was wrong with the Catholic faith and leadership. The opening salvo of the Reformation had been fired. Reformer protested against the Roman Catholic Faith and soon refereed in general by the title of Protestants. From 1517, to the end of the thirty Years War in 1648, Europe would be wracked by religious bloodshed.
Martin Luther by Lucas Cranach the Elder-1533. A monk in Germany, Luther (1483-1546) found fault with many aspects of the Catholic faith, especially its basic theology, political and economic policies. His Ninety-Five Theses, started a rift between those that supported the Roman Catholic faith and those that protested against the Pope and his followers-the Protestant movement to Reform the Christian Faith and Church had begun. The followers of Luther eventually formed Lutheranism which today is the Majority religion in: Denmark (Official National Religion), Estonia, Finland (Official National Religion), Greenland, Iceland (Official National Religion), Latvia, Namibia, Northern Germany, Norway (Official National Religion), and Sweden.
John Calvin by René Boyvin in 1562. Born in France, Calvin (1509-1564) became a leading theologian in the Reform movement. His concepts formed the basis of Calvinism (aka Reformed Theology or Faith) and the Presbyterianism movements. Famous adherents of the concepts of Calvinism included the Pilgrims, Puritans, Huguenots, Scottish Presbyterians and the "Reformed Churches."
John Knox (1514-1572) from Scotland, a former Catholic priest, he was a major leader of the Reformation and was instrumental in the formalization of much of concepts of Calvinism into Presbyterianism.
King Henry VIII (1491-1547)-Church of England (Anglican). Mainly for political reasons, King Henry VIII established the Church of England (COE) in 1534, with the monarch as the head of the church with all the powers of appointment and ownership of all church properties under the rulers control. Years of unrest during the Tutor Dynasty eventually resulted in the COE becoming the defacto national religion of England.
Once the seriousness of the Reformation was acknowledged in Rome, the Catholic Church began its own Counter Reformation to stem the tide of gains the Protestants were making among the Christians of Europe. A grand meeting, the Council of Trent (met from 1545-1563), to address many of the challenges and reforms were instituted. Friendly monarchs were encouraged to make war upon Protestant rulers to win lands and people back by the sword if necessary, and the dreaded Inquisition was given full authority to "root out heretics" by what ever means were necessary.
One of the Catholics strongest forces in the Counter Reformation were the members of the Society of Jesus-Jesuits, a new order of highly educated priests. Established by Ignatius Loyola (1491-1556) to win back protestants through missionaries with educated argument guile. Education was seen as a key to winning back converts so many schools and Universities were establish under Jesuit leadership ( in 2012 there were 28 Jesuit colleges and universities and more than 50 secondary schools in the USA alone).
By the end of the 17th century the Roman Catholics had retained control of the following: Austria, Belgium, France, Hungary, Ireland, Italy, Monaco(Official National Religion), Poland, Portugal, Southern Germany and Spain.
The Protestant vs Catholic Religious wars were largely over by the 1700's but the division between the two Cristian groups would continue to grow and influence World affairs for centuries to come.