4th Spanish Armada in the context of "Nine Years' War (Ireland)"

Ireland was conquered by the Tudor monarchs of England in the 16th century. The Anglo-Normans had conquered swathes of Ireland in the late 12th century, bringing it under English rule. In the 14th century, the effective area of English rule shrank markedly, and from then most of Ireland was held by native Gaelic chiefdoms. Following a failed rebellion by the Earl of Kildare in the 1530s, the English Crown set about restoring its authority. Henry VIII of England was made "King of Ireland" by the Crown of Ireland Act 1542. The conquest involved assimilating the Gaelic nobility by way of "surrender and regrant"; the confiscation and colonisation ('plantation') of lands with settlers from Britain; imposing English law and language; banning Catholicism, dissolving the monasteries, and making Anglican Protestantism the state religion.

The Tudor policies in Ireland sparked the Desmond Rebellions (1569–1573, 1579–1583) and the Nine Years' War (1594–1603). Despite Spain sending an armada to support the Irish Catholics during the Anglo-Spanish War (1585–1604), by 1603 the entire country was under English rule. The Flight of the Earls in 1607 largely completed the destruction of the Gaelic aristocracy and left the way open for the Plantation of Ulster, which established a large British Protestant population in the north. Several people who helped establish the plantations of Ireland also played a part later in the early colonisation of North America, particularly a group known as the West Country Men.

The siege of Kinsale (Irish: Léigear Chionn tSáile), also known as the battle of Kinsale, was the ultimate battle in England's conquest of Gaelic Ireland, commencing in October 1601, near the end of the reign of Queen Elizabeth I, and at the climax of the Nine Years' War—a campaign by Hugh O'Neill, Hugh Roe O'Donnell and other Irish lords against English rule.

Owing to Spanish involvement and the strategic advantages to be gained, the battle also formed part of the Anglo-Spanish War, the wider conflict of Protestant England against Catholic Spain.