Causes
The south of Ireland (the provinces of Munster and southern Leinster) was dominated, as it had been for over two centuries, by the Old English Butlers of Ormonde and the FitzGeralds of Desmond, who maintained feudal principalities. Both houses raised their own armed forces and imposed their own law, a mixture of Irish and English customs independent of the English government of Ireland. Beginning in the 1530s, successive English administrations in Ireland tried to expand English control over the entire island (See Tudor conquest of Ireland). By the 1560s, their attention had turned to the south of Ireland and Henry Sidney, as Lord Deputy of Ireland, was charged with establishing the authority of the English government over the independent lordships there. His solution was the formation of "lord presidencies"—provincial military governors who would replace the local lords as military powers and keepers of the peace.
The local dynasties saw the presidencies as intrusions into their sphere of influence, and into their traditional violent competition with each other. This had seen the Butlers and FitzGeralds fight a pitched battle against each other at Affane in County Waterford in 1565. This was a blatant defiance of the Elizabethan state's law. Elizabeth I summoned the heads of both houses to London to explain their actions. However, the treatment of the dynasties was not even handed. Thomas Butler, 3rd Earl of Ormonde — who was the Queen's cousin — was pardoned, while both Gerald FitzGerald, 14th Earl of Desmond (in 1567) and his brother, John of Desmond, widely regarded as the real military leader of the FitzGeralds, (in 1568) were arrested and detained in the Tower of London on Ormonde’s urging.
This decapitated the natural leadership of the Munster Geraldines and left the Desmond Earldom in the hands of a soldier, James FitzMaurice FitzGerald, the "captain general" of the Desmond military. Fitzmaurice had little stake in a new de-militarised order in Munster, which envisaged the abolition of the Irish lords’ private armies. A factor that drew wider support for Fitzmaurice was the prospect of land confiscations, which had been mooted by Sidney and Peter Carew, an English claimant to lands granted to an ancestor just after the Norman conquest of Ireland that were lost soon afterwards.
This ensured Fitzmaurice the support of important clans, notably MacCarthy Mor, O'Sullivan Beare and O'Keefe and two prominent Butlers –brothers of the Earl. Fitzmaurice himself had lost the land he had held at Kerricurrihy in County Cork, which had been leased instead to English colonists. He was also a devout Catholic, influenced by the counter-reformation, which made him see the Protestant Elizabethan governors as his enemies. To discourage Sidney from going ahead with the Lord Presidency for Munster and to re-establish Desmond primacy over the Butlers, he planned a rebellion against the English presence in the south and against the Earl of Ormonde. Fitzmaurice however had wider aims than simply the recovery of FitzGerald supremacy within the context of the English Kingdom of Ireland. Before the rebellion, he secretly sent Maurice MacGibbon, Catholic Archbishop of Cashel, to seek military aid from Philip II of Spain.
Read more about this topic: Desmond Rebellions