The Royal Navy, having been tipped off about the shipment waylaid the boat, which was promptly scuttled by the captain, and the crew captured. The Lord Lieutenant of Ireland in Dublin — the nerve center of British control of Ireland — was put on alert, but before measures could be taken for defense, the rising began on Easter Monday. Twelve hundred armed Irish volunteers assembled in Dublin and began sealing off streets and seizing strategic locations near the town center. Soldiers and police were gunned down when they tried to respond, and the city of Dublin became a war zone. The rebels failed to capture the castle or the ports, probably for lack of men, but held the post office as headquarters till it caught fire from canon shells and burned down, leaving only the façade. The fighting was street-to-street and house-to-house. Smaller risings across Ireland were also attempted but with very little success. British reinforcements overwhelmed the rebels and a truce was struck six days after the fighting began.
About 485 people died in the rising, more than half of them civilians. About 2,600 were wounded. The reprisals were deadly. Secret trials condemned ninety to death, the British authorities carried out fifteen executions, including most of the leaders of the Irish Brotherhood, and several others, without previous judicial warrant. The executions engendered much sympathy from Ireland, Britain and America. Irish independence organizations resorted to arms again in 1921, with many more casualties and horrors visited on Ireland by both sides. Britain created the Irish Free State in 1922. For all practical purposes, Henry VIII and his successors were history, at least in the counties below Ulster.