Eoin Mac Neill was born in Glenarm, County Antrim, and was educated at St Malachy's College, Belfast, and the Royal University of Ireland. He worked as a civil servant and in 1893 he was a founder member of the Gaelic League, editing its publication, the Gaelic Journal. From 1908 to 1945 he was Professor of Early Irish History at University College, Dublin. He became a commander of the Irish Volunteers, which he had helped to organise, and on Easter Sunday 1916 he countermanded orders for the Easter Rising because he felt that there could be no success. He was imprisoned and released in 1917. In 1918 he was elected member of parliament for the National University of Ireland. From 1922 to 1925 he was Minister for Education and served on the 1925 Boundary Commission, from which he resigned, just as its report was about to be published, and he retired thereafter from active politics. In 1927 he was appointed Chairman of the Irish Manuscripts Commission. He published Phases of Irish History; Celtic Ireland; St Patrick and Early Irish Laws and Institutions.