Great Rebellion

Revolt against the English government in Ireland between 1641 and 1650. It was supported by the Old Irish (descendants of the original Gaelic inhabitants) and Norman-Irish (descendants of Norman settlers). Their killing of Protestant planters, settlers of confiscated Catholic land, and intrigue with Charles I during the English Civil War (1641–49), led to massive confrontation with Oliver Cromwell's Parliamentary forces during Cromwell's Irish campaign (1649–50). His victory led to the dominance of Irish Protestantism over the Roman Catholic majority in Ireland.

The roots of the rebellion lay in the Plantation of Ireland in the 16th and 17th centuries, when loyal Protestant English and Scottish settlers were planted on lands confiscated from Catholic Irish rebels. The rebellion was also inspired by hatred of the rule of Thomas Wentworth, Earl of Strafford, the lord deputy of Ireland, and by fear of what would happen if the Puritan lord justices took over the administration.

Thousands of Protestant planters in Ireland were killed, the most notorious incident being the Portadown Bridge massacre in 1641. The situation was complicated by the outbreak of the English Civil War in England as the Irish sent some help to King Charles I, who was continually intriguing with them. In 1649 the execution of Charles I marked the victory of Parliament and the establishment of Oliver Cromwell's Commonwealth. Parliamentary troops were released for service in Ireland, where the new king, Charles II, had immediately been recognized and Cromwell's whirlwind Irish campaign began in August 1649. By the end of his campaign in May 1650 Cromwell's troops had effectively ended any concerted military opposition to English parliamentary rule.

The victory of the Puritan Parliamentary forces reinforced the fact that Protestantism had become as much a political idea as a religious one. The Protestant minority were given even greater control over the Catholic majority. The atrocities committed on both sides during the Great Rebellion, such as at Portadown Bridge in 1641, and the battles of Drogheda and Wexford in 1649, left a profound resentment that fuelled Catholic Irish nationalism and Irish republicanism, as well as Protestant unionism.