1418 in Ireland

The Kingdom of Desmond was a historic kingdom in southwestern Ireland. It was founded in 1118 by Tadhg Mac Cárthaigh, King of Munster when the Treaty of Glanmire formally divided the Kingdom of Munster into Desmond and Thomond. It comprised all of what is now County Cork and most of County Kerry. Desmond was ruled by the Mac Cárthaigh (MacCarthy) dynasty. Other clans within the kingdom included the O'Sullivans and O'Donovans. Following the Norman invasion of Ireland in the late 12th century, the eastern half of Desmond was conquered by the Anglo-Normans and became the Earldom of Desmond, ruled by the Fitzmaurices and FitzGeralds—the famous Irish family known as the Geraldines. The king of Desmond, Diarmaid Mac Cárthaigh submitted to Henry II of England, but the western half of Desmond lived on as a semi-independent Gaelic kingdom. It was often at war with the Anglo-Normans. Fínghin Mac Carthaigh's victory over the Anglo-Normans at the Battle of Callann (1261) helped preserve Desmond's independence. The kings of Desmond founded sites such as Blarney Castle, Ballycarbery Castle, Muckross Abbey and Kilcrea Friary. Following the Nine Years' War of the 1590s, Desmond became part of the Kingdom of Ireland.

The Desmond Rebellions occurred in 1569–1573 and 1579–1583 in the Irish province of Munster. They were rebellions by the Earl of Desmond, the head of the FitzGerald dynasty in Munster, and his followers, the Geraldines and their allies, against the threat of the extension of the English government over the province. The rebellions were motivated primarily by the desire to maintain the independence of feudal lords from their monarch but also had an element of religious antagonism between Catholic Geraldines and the Protestant English state. They culminated in the destruction of the Desmond dynasty and the plantation or colonisation of Munster with English Protestant settlers. 'Desmond' is the Anglicisation of the Irish Deasmumhain, meaning 'South Munster'.

Thomas Butler, 10th Earl of Ormond and 3rd Earl of OssoryPC (Ire), was an influential courtier in London at the court of Elizabeth I. He was Lord Treasurer of Ireland from 1559 to his death. He fought for the crown in the Rough Wooing, the Desmond Rebellions, and Tyrone's Rebellion. He fought his rival, Gerald FitzGerald, 14th Earl of Desmond in the Battle of Affane in 1565.

Piers Butler, 8th Earl of Ormond, 1st Earl of Ossory also known as Red Piers, was from the Polestown branch of the Butler family of Ireland. In the succession crisis at the death of Thomas Butler, 7th Earl of Ormond he succeeded to the earldom as heir male, but lost the title in 1528 to Thomas Boleyn. He regained it after Boleyn's death in 1538.

The Battle of Affane was fought in County Waterford, in south-eastern Ireland, in 1565, between the forces of the Fitzgerald Earl of Desmond and the Butler Earl of Ormond. The battle ended in the rout of the Desmond forces. It was one of the last private battles fought in Britain or Ireland.

Margaret Butler, Countess of Ormond, Countess of Ossory was an Irish noblewoman and a member of the powerful and celebrated FitzGerald dynasty also known as "The Geraldines". She married Piers Butler, 8th Earl of Ormond, by whom she had three sons and six daughters.

John Butler of Kilcash was an Irish landowner and soldier. A younger son of James Butler, 9th Earl of Ormond and brother of Thomas Butler, 10th Earl of Ormond, he received Kilcash Castle as appanage. He fought in the Desmond–Ormond conflict and was badly wounded in 1563, just before the Battle of Affane. He was the start-point of the Kilcash branch of the Ormonds and the father of Walter Butler, 11th Earl of Ormond.

James FitzGerald, 6th Earl of Desmond, called 'the Usurper', was a younger son of Gerald FitzGerald, 3rd Earl of Desmond, and Lady Eleanor, daughter of James Butler, 2nd Earl of Ormond.

James fitz John FitzGerald, 13th Earl of Desmond, also counted as the 14th, ruled 22 years, the first 4 years as de facto earl until the death of James FitzGerald, de jure 12th Earl of Desmond, called Court Page, who was murdered by James fitz John's brother Maurice fitz John FitzGerald, called Totane. James fitz John FitzGerald maintained himself in power by skilful diplomacy, avoiding armed conflict and destruction. He was appointed Lord Treasurer of Ireland in 1547.

James fitz Maurice FitzGerald, de jure 12th Earl of Desmond, also counted 13th, was called Court Page as he grew up as a hostage for his grandfather Thomas FitzGerald, 11th Earl of Desmond, the Bald, at the court of Henry VIII. He should have succeeded this grandfather in 1534, but John FitzGerald, de facto 12th Earl of Desmond usurped the earldom and was followed in 1536 by his son James, fitz John. In 1539 the lord deputy of Ireland, Leonard Grey seized some Desmond land in southern County Cork and handed it to Court Page, who came to Ireland to claim his rights but was killed by Maurice fitz John FitzGerald, called Totane. He was succeeded by James fitz John, now rightful 13th earl.

Cormac Oge Laidir MacCarthy, 10th Lord of Muskerry (1447–1536) was an Irish chieftain, styled Lord of Muskerry. In 1520 he defeated James FitzGerald, 10th Earl of Desmond in the battle of Mourne Abbey.