Hostilities began about noon on April 24, when about 2000 men led by Pearse seized control of the Dublin post office and other strategic points within the city. Shortly after these initial successes, the leaders of the rebellion proclaimed the Independence of Ireland and announced the establishment of a provisional government of the Irish Republic. Additional positions were occupied by the rebels during the night, and by the morning of April 25 they controlled a considerable part of Dublin. The counteroffensive by British forces began on Tuesday with the arrival of reinforcements. Martial law was proclaimed throughout Ireland. Bitter street fighting developed in Dublin, during which the strengthened British forces steadily dislodged the Irish from their positions. By the morning of April 29, the post office building, site of the rebel headquarters, was under violent attack. Recognising the futility of further resistance, Pearse surrendered unconditionally in the afternoon of April 29.
The British immediately brought the leaders of the uprising to trial before a field court-martial. Fifteen of the group, including Pearse, Connolly, and MacDonagh, were sentenced to death and executed by firing squad. Four others, including the American-born Eamon de Valera, received death sentences that were later commuted to life imprisonment, although de Valera and some others were granted amnesty the next year. Casement was convicted of treason and hanged. Many others prominently connected with the rebellion were sentenced to long prison terms. The uprising was the first of a series of events that culminated in the establishment of the Irish Free State (predecessor of the Republic of Ireland) in 1921. Casualties were about 440 British troops and an estimated 75 Irish (below are their names). Property damage included the destruction of about 200 buildings in Dublin.