The Kingdom of Desmond (Irish: Deasmhumhain, meaning 'South Munster') 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 (Tuadh-Mhumhain, "North Munster"). 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