Just as peace was descending over Scotland and England, Ireland erupted into war. Across Ulster and down into southern Ireland, English and Scottish planters, their wives and children, were put to the sword. Over 15,000 Protestants and then Catholics were murdered or left to die of exposure in the harsh Irish winter. Revenge attacks engulfed the entire region as Protestant and Catholic fought it out for land and religion. Communities collapsed into anarchy and previously content neighbours carried out brutal executions. Ireland became the Balkans of the seventeenth century.
The Irish rebellion added a terrible momentum to the War of the Three Kingdoms. The intervention of Ireland into the English Civil War proved fatal to Charles I. The frail peace between King and Parliament was blown wide apart. In the words of the King's supporter, Earl Clarendon, 'though Scotland blew the first trumpet, it was Ireland that drew the first blood; and if they had not at that time rebelled, and in that manner, it is very probable all the miseries which afterwards befell the king and his dominions had been prevented'. England, Scotland, Ireland and Wales were facing total war.
The Irish Rebellion of 1641 unleashed a wave of sectarian killing that still disfigures Anglo-Irish politics to the present day. The massacre of Protestant settlers by Irish Catholics set in train many of the myths, legends and blood feuds which still bedevil contemporary Ulster.
Why did Ireland suddenly erupt into bloodshed? Most landowners and politicians were surprised by the bloody violence that gripped the island. To understand what unleashed this carnage, we need to understand Ireland's bitter history.
Gaelic Ireland had been colonised since the Middle Ages by English settlers known as the 'Old English' who were, for the most part, Roman Catholics. The 17th Century saw a new wave of settlers from England and Scotland who were Protestant. Since the time of Elizabeth, English monarchs needed an expensive standing army to govern Ireland. James I abandoned that policy and instead planted Protestant settlers on land taken from the indigenous Irish as a means of exerting English power. The massive 1609 Plantation provided a form of Irish self-governance. It was a brutal policy of forced migration which set in train the entire tragedy of the Irish troubles. It bitterly alienated the dispossessed Irish chieftains and drove the 'Old' English closer to the Irish.
The policy caught up with the Crown in 1625 when Charles I declared war against Spain. He urgently needed to raise money and increase the military presence in Ireland to guard against possible Spanish invasion. To ensure the support of the 'Old' English and the Irish, he agreed to a series of concessions on religion known as 'The Graces'. The militant Protestant settlers denounced these favours - calling them 'religion for sale.' The language of betrayal was already endemic in Irish politics. Amidst this chaos, Charles sent in his trusted aide and bully-boy, the Earl of Strafford, to control the situation.
Strafford only managed to make matters worse - antagonising the 'Old' English by promoting more plantation and disturbing the settlers by enforcing the Crown's interests against any encroachments on its land. He called his strategy 'Thorough' - it was a means of 'civilising...this people, or securing this kingdom under the dominion of your imperial Crown.' Marginalised on barren land, the native Irish fell ever more heavily into debt, saw their Catholic religion threatened, and their future prosperity undermined. By the late 1630s, relations between the Irish and the settler communities were at breaking point.
The spark for the rebellion lay in the billiard ball effect of the multiple kingdom. One policy in one kingdom could produce terrible results in another. Charles was once asked, 'how can you affect your end without the haserding of your three crownes?' The answer was that he couldn't.
The closer Charles I came to conciliating Pym and the Scottish Covenanters, the greater the threat he created to the stability of his Irish kingdom. As the King looked on the verge of agreeing to a more radical Protestant policy, the Catholic Irish felt ever more afraid. A Presbyterian settlement could only mean further religious discrimination and loss of land for the old Catholic families. The Gaelic chieftans had seen the success enjoyed by the Covenanters in Scotland and decided that rebellion was the only language Charles understood. But what began, like the National Covenant, as a controlled uprising against the English administration in Dublin was quickly over taken by long-term resentment. In October 1641, the Gaelic clans of Dungannon, Charlemont and Newry rose against the Protestant settlers who occupied their ancient estates. The rebellion fanned out across the island in an uncontrolled and savage fashion.