Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Seán Mac Diarmada (February 28, 1883 May 12, 1916) (born John MacDermott, usually used the name Sean MacDermott) was one of the leaders of the 1916 Easter Rising in Ireland. Mac Diarmada was born in Kiltyclogher County Leitrim, where he was educated by the Irish Christian Brothers. In 1908 he moved to Dublin, by which time he already had a long involvement in several Irish separatist and cultural organizations, including Sinn Féin, the Irish Republican Brotherhood, the Ancient Order of Hibernians and the Gaelic League. He was soon promoted to the Supreme Council of the IRB and eventually elected secretary.