Charles William St John Burgess (Cathal Brugha) (18 July 1874-7 July 1922) was an Irish revolutionary, born in Dublin, who was active in the Easter Rising and the Irish Civil War.

He was educated at Belvedere College but was forced to leave at the age of sixteen due to the failure of his father's business. Brugha went on to become a clerk with a church supplies firm.

In 1899 Brugha joined the Gaelic League and in 1913 he became lieutenant in the Irish Volunteers. During the Easter Rising in 1916 he was second in command at South Dublin Union under Commandant Eamonn Ceannt. During the fighting he was severely wounded by a hand grenade. He also had a prominent role in the Anglo-Irish War. In October 1917 he became Chief of Staff of the Irish Republican Army and held that post until April 1919. In 1918 he was elected to Dáil Éireann representing Waterford and he soon became Minister for Defence. Due to the abscence of Eamon de Valera and Arthur Griffith, Brugha presided over the first meeting of Dáil Éireann on the 21 January 1919.

In 1922 he voted against the Treaty and was quickly replaced as Minister for Defence by Richard Mulcahy. During the Irish Civil War he fought on the anti-Treaty side but was severely wounded again. Cathal Brugha died on 7 July 1922 from the wounds he received.

|- style="text-align: center;" | width="30%" |Preceded by:
Richard Mulcahy | width="40%" style="text-align: center;" |Minister for Defence
1919-1921 | width="30%" |Succeeded by:
Richard Mulcahy