In the 17th century, Parliament had become an important aspect in the political life of England. When King Charles I (r. 1625-1649) threatened the power of this institution with his more absolutist policy, it lead to a civil war which had a completely unprecedented conclusion.
Catholicism was greatly feared and hated in England after the Reformation of Henry VIII and especially after Mary Tudor. Charles I had taken a Catholic wife, and the people were worried that he would raise his children Catholic. In addition, Archbishop Laud of Canterbury was less protestant in his religious policy, somewhat favoring the pomp and ceremony of the old Catholic Church. He also emphasized the aspect of communion in the worship service, and not the sermon, which was a very Catholic practice. The religious policy of Laud prompted a revolt by the Scottish which Charles had insufficient funds to suppress. He had been refused money by parliament for previous military undertakings, so he sought other means to raise funds. He dug up old and forgotten laws and edicts in search for revenue, but his endeavors did not prove fruitful enough. Finally, he summoned Parliament again (called Long Parliament, lasting from 1640 to 1660). At this meeting he was forced to give Parliament a far greater degree of autonomy, and to remove Archbishop Laud. Parliament was happy that it had extracted more privileges, but it realized that Charles could just be biding his time until was back on his feet financially, and would retract his promises later.
War broke out between the royalist Cavaliers and the Parliamentarian Roundheads in 1642. The Roundheads had a new organization of military, called the New Model Army, which was based in London rather than locally. The Royalists were defeated in 1645 and Charles was captured in 1646. A second civil war broke out in 1648, and in January of 1649, something unprecedented occurred: Charles was executed. This was quite revolutionary. That the legitimate ruler could be executed was shocking to the world, and shaped the development of Western Civilization in the centuries to come.