They agreed to help the king as long as he abandoned his absolutist ways. He did not like this proposition and attempted to arrest four of the Puritan leaders at the House of Commons. Oliver Cromwell, one of the men Charles was after, announced that if any member of parliament was arrested that it would be considered a crime of treason against the king. Then they declared Civil War against the king. This clearly caused political conflict in the government. Roundheads, led by John Pym, supported the parliament; these were mostly puritans, middle class and small landowners. On the other hand, Cavaliers supported king Charles I; these were mostly the upper class, big landowners, Anglicans and Catholics. They were led by Charles I and his nephew Prince Rupert of the Palatinate. In the first few battles the Cavaliers had the upper hand. Cromwell trained his own army and led them as the New Model Army. They defeated the king's forces at the Battle of Marston Moor and the Battle of Naseby. In desperation, the king called in the Scots and Irish catholic troops for help. Finally the king was defeated and became a prisoner of parliament. Cromwell then created the Rump Parliament and urged that the king should be put on trial for his crimes. The Parliament during the trial had the upper hand over the king and had the power and support of the people. This is clearly illustrated in the drawing of Charles I on trial before commons, 1649. (Doc.4) The king was tried, convicted and beheaded in public for all to see. This reinstated that English kings rule was by law and not divine right.
Oliver Cromwell ruled in England as "Lord Protector of England". England was declared a commonwealth or a republic. Cromwell was very liked by the people he helped England by creating a marine fleet, encouraged the return of the Jews to England ,supported the arts and sponsored many ventures to the Americas. But with the more power he got he started to act like a dictator he dismissed the Rump Parliament that he had created, he was intolerant of the Anglican Church, created new taxes and Massacred thousands of Irish people in Massacre of Drogheda.