Throughout the 1640s, the wars received momentum from the complex relationship between the three kingdoms of England, Ireland and Scotland. And while Charles's arrogance towards Scotland began the troubles, it was Ireland which really set it alight.
From the early 1600s both Elizabeth I and then James I (Charles's father) had introduced Protestant farmers into Catholic, Gaelic Ireland. This was a means of governing Ireland without the cost of a standing army, as well as a way to generate more tax revenue. With the backing of the Crown, the settlers drove the Gaelic clans from the fertile land - a policy of forced migration. By the late 1630s, relations between the two communities were at breaking point. Following the example set by the Scottish Covenanters, the Gaelic chieftains rose up in 1641 and attacked the Protestant settlers in an attempt to force a change of policy from the Crown.
The vital importance of the Irish rebellion to the English civil war was that it led to a constitutional struggle between King and Parliament over the control of the army needed to crush the Gaelic rebels. It led to the Parliamentary leader John Pym issuing a Grand Remonstrance, the King fleeing London and the emergence of Cavaliers and Roundheads - a division which not only caused damaging splits between old friends but also painful fissures between members of the same family.
The Roundheads feared Charles in control over an army given his history of authoritarianism and dangerous reforms to the Church of England. The Cavaliers, on the other hand, were opposed to the religious radicals, or Puritans, in Parliament taking control of the Church of England. They also believed rebelling against a King was unlawful, even sinful.
In England, the sides were set and Charles raised his standard in August 1642. The battle which was meant to solve the crisis one way or another took place at Edgehill in October 1642. But despite the flamboyant bravery of Charles's finest soldier, Prince Rupert, and the dogged persistence of the Parliamentary commander, the Earl of Essex, neither side achieved the crushing victory required, and both sides instead prepared for a long, bloody war.
In spring 1644, a Scottish Covenanter Army poured into northern England to offer assistance to their Parliamentary allies to help break the stalemate. They headed for York where a Royalist garrison was under siege. At the same time, Prince Rupert marched north, determined to lift the siege and teach the Parliamentary rebels a bloody lesson. In July 1644, the two sides came into collision just outside York on the fields of Marston Moor.
The Irish Dimension is extremely important in understanding the origins of the English Civil War. By mid-1641, Charles had settled his differences with the English Parliament and was on his way north to make peace with the Scots. When Ireland exploded in rebellion in November, it drew the sovereign into conflict with his subjects and set the three kingdoms on the path to prolonged and bloody conflict.
Relations between Parliament and King were especially tense during 1641-2. In time of war, Charles expected Parliament to provide him with soldiers and funds, but what he received was the Grand Remonstrance, a document outlining eleven years of alleged religious and political abuse. When Charles tried and failed to arrest his Parliamentary opponents in January 1642, conflict between Crown and Parliament became inevitable.
Charles' departure from London and the growing rift with Parliament forced people to start taking sides during 1642. Family ties and long-standing friendships were placed under intolerable pressure as the country started to polarise. When Charles raised his standard at Nottingham in August 1642, the scene was set for war.
The opening twelve months of the war were inconclusive. Edgehill was a draw and the two sides drew back from major conflict at Turnham Green. A truce in Ireland released troops to join the Royalist cause, while Parliament entered into a Solemn League and Covenant with the Scots Presbyterians in September 1643. Following Royalist advances in the north-west during 1644, Charles ordered his nephew to relieve the siege of York, a decision which was to have fateful consequences.