Events Leading up to the War
The English civil war was a complicated war involving strange loyalties and religious tensions. To learn how it started we have to look back to the time of the Scottish King James I (IV in Scotland, 1603 to 1625). He ruled very differently to the tudors before him and his belief in empowerment was not through the people but through the belief that it was his god given right. This made him unpopular with parliament, this was impacted by his insistence on controlling foreign policy, which he did with limited success. By the time of his death in 1625, Parliament had little confidence or trust in the monarchy.
This mistrust was not helped when his son Charles I came to power, although with a more relaxed approach to christianity, he still believed his power was divine. His relaxed version of Christianity was known as Arminianism, he used his bishops to attempt to make this the uniformly accepted version across the land. Charles belief in his power as King went on to rule England for 11 years without parliament.
It was Charles insistence on religious uniformity that was causal in the downfall of English rule in Scotland. When he tried to impose Arminianism on a largely Presbyterian population in Scotland (1637) it caused a rebellion.
The Beginnings of War
The Scots invaded, reaching Newcastle in 1641. Charles attempted to recall Parliament in order to help defend England. After failing once, the cost was high resulting in increased parliamentary power over the land and restrictions for the monarchy. In 1642, Charles made a grave error by attempting to arrest his main rivals in the House of Commons, this direct attack deepened the rift between the Monarchy and Parliament beyond repair. In August he made a stand in Nottingham and declared war on Parliament. The English Civil War with the Parliamentarians 'Roundheads' on one side and the Royalists 'Cavaliers' on the other, this was largest War of the classes in British history! The country was divided by class and more importantly religion, initially it seemed as though the King had the majority support. The King rallied support from the Celts in Cornwall, Wales and Ireland. And in 1645 the Scots decided that their interests were not with the Parliamentarians, Charles was later able to gain their support.
But Charles key mistake was in the recruitment of so many foreign troops and mercenaries. Many of the people who sided with the King, who believed they were fighting for the good of England became disillusioned by this and switched sides in their droves. The balance very quickly became tipped.
In the meantime an MP called Oliver Cromwell and a number of other MP's resigned their position in the House of Commons and created the New Model Army with Cromwell at its head.
The now well trained and disciplined Roundhead armies were more than a match for Charles I, defeat seemed unavoidable. In June 1646, Oxford was taken by Cromwell's New Model Army, the King fled to the Scots who handed him to Parliament where he was later executed by Parliament in January 1649. The Civil War which had raged since 1642 seemed to be over in that June of 1646.