1536–1691

From 1536, Henry VIII decided to re-conquer Ireland and bring it under crown control. The Fitzgerald dynasty of Kildare, who had become the effective rulers of Ireland in the 15th century, had become very unreliable allies of the Tudor monarchs. They had invited Burgundian troops into Dublin to crown the Yorkist pretender, Lambert Simnel as King of England in 1487. Again in 1536, Silken Thomas Fitzgerald went into open rebellion against the crown. Having put down this rebellion, Henry VIII resolved to bring Ireland under English government control so the island would not become a base for future rebellions or foreign invasions of England. In 1541, Henry upgraded Ireland from a lordship to a full Kingdom. Henry was proclaimed King of Ireland at a meeting of the Irish Parliament that year. This was the first meeting of the Irish Parliament to be attended by the Gaelic Irish chieftains as well as the Hiberno-Norman aristocracy. With the institutions of government in place, the next step was to extend the control of the English Kingdom of Ireland over all of its claimed territory. This took nearly a century, with various English administrations in the process either negotiating or fighting with the independent Irish and Old English lords. The Spanish Armada in Ireland suffered heavy losses during an extraordinary season of storms in the autumn of 1588. Among the survivors was Captain Francisco de Cuellar, who gave a remarkable account of his experiences on the run in Ireland.^[8]

The re-conquest was completed during the reigns of Elizabeth and James I, after several extremely brutal conflicts. (See the Desmond Rebellions (1569–1573 and 1579–1583 and the Nine Years War 1594–1603, for details). After this point, the English authorities in Dublin established real control over Ireland for the first time, bringing a centralised government to the entire island, and successfully disarmed the native lordships. However, the English were not successful in converting the Catholic Irish to the Protestant religion and the brutal methods used by crown authority (including resorting to martial law) to bring the country under English control heightened resentment of English rule.

From the mid-16th and into the early 17th century, crown governments carried out a policy of colonisation known as Plantations. Scottish and English Protestants were sent as colonists to the provinces of Munster, Ulster and the counties of Laois and Offaly (see also Plantations of Ireland). These settlers, who had a Protestant identity, would form the ruling class of future British administrations in Ireland. A series of Penal Laws discriminated against all faiths other than the established (Anglican) Church of Ireland. The principal victims of these laws were Catholics and later Presbyterians.

The 17th century was perhaps the bloodiest in Ireland's history. Two periods of civil war (1641-53 and 1689-91) caused huge loss of life and resulted in the final dispossession of the Irish Catholic landowning class and their subordination under the Penal Laws.

In the mid-17th century, Ireland was convulsed by eleven years of warfare, beginning with the Rebellion of 1641, when Irish Catholics rebelled against English and Protestant domination, in the process killing thousands of Protestant settlers. The Catholic gentry briefly ruled the country as Confederate Ireland (1642-1649) against the background of the Wars of the Three Kingdoms until Oliver Cromwell re-conquered Ireland in 1649-1653 on behalf of the English Commonwealth. Cromwell's conquest was the most brutal phase of a brutal war. By its close, up to a third of Ireland's pre-war population was dead or in exile. As punishment for the rebellion of 1641, almost all lands owned by Irish Catholics were confiscated and given to British settlers. Several hundred remaining native landowners were transplanted to Connacht.