Sir John Perrot was a member of the Welsh gentry who served as Lord Deputy of Ireland under Queen Elizabeth I of England during the Tudor conquest of Ireland. It was formerly speculated that he was an illegitimate son of King Henry VIII, though the idea is rejected by modern historians.Sir John Perrot, was a figure of unusual power and influence in Tudor Britain and Ireland. Born near Haverfordwest in 1528, he inherited wealth and power – the Perrots had been accumulating both in west Wales for centuries – and gained more ingratiating himself with the English court. His own son described him as a "very cholericke" man, who "could not brooke any crosses". He had already gathered many offices by the time he was sent to Ireland in 1571 as President of Munster to suppress a rebellion. His methods were characteristically violent – he hanged over 800 of the rebels – but he resigned after two years, having failed in his mission.Back in west Wales he contented himself with self-enrichment and self-glorification, rebuilding in grand style his two main homes, Carew Castle and Laugharne Castle. He returned to Ireland as 1584 as Lord Deputy, with the task of crushing the Irish and colonising their land. Again unsuccessful, he returned, was falsely accused of treason by his many enemies, and died in the Tower of London in 1592, possibly of poisoning.

The Tudor conquest of Ireland took place during the 16th century under the Tudor dynasty, which ruled the Kingdom of England. 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 colonization ('plantation') of lands with settlers from Britain; imposing English law and language; banning Catholicism, dissolving the monasteries and making Anglican Protestantism the state religion.