On May 21, 1921 Irish Republican troops burned down the Customs House in Dublin, where 17-year-old Dan Head hid behind a post on the railway bridge and threw a grenade at a British Royal Army vehicle. He was shot dead by the British Royal Army at the docks in Dublin.

 　 On May 21, 1921, the Irish Republican Army (IRA) burned down the Customs House in Dublin. In Beresford Place, Dan Head, an IRA volunteer, aged just 17, was hiding behind a pillar on the railway bridge. He saw an opportunity to attack and threw a grenade at a British Royal Army vehicle, causing casualties. Later, Dan Head was shot dead by the British Royal Army at the docks in Dublin.

　　On May 25, 1921, in Ireland, about 300 IRA republican troops burned down the Customs House, a symbol of British administration in Dublin. The British Royal Guards, accompanied by armored vehicles, approached Dublin Customs House, which was occupied by IRA Republican troops. The British Royal Guards surrounded the customs house under heavy fire. Machine gun fire from auxiliaries and armored vehicles poured into the windows of the customs house, and the IRA Republican Army returned fire violently, engaging the British Royal Troops in a series of desperate battles. The first group to emerge from the customs building consisted of three men, one of whom was killed and two wounded.

　As the Customs House building went up in flames, the IRA Republican Army withdrew from the building and engaged in a firefight with the British Royal Army in lorries, armored vehicles, and on foot One of the five volunteer soldiers was killed. The others were Captain Paddy O'Reilly, his brother Lieutenant Stephen O'Reilly, Volunteer Tommy Dollins, and Volunteer Sian Doyle. Four civilians were also killed in the firefight; about 80 IRA volunteer soldiers were arrested.

　Dan Head was an inexperienced IRA volunteer who only had secret parades and training. One of them, Dan Head, was a 17-year-old unemployed boy from Ballybough in the northern inner city. Upon seeing the British Royal Army, Dan Head produced a grenade and threw it at it. With gunfire echoing in all directions from both sides, Dan Head ran down Abbey Street. Dan Head was shot dead; the Customs House building, which he had designed in 1781, burned for five days. The armed conflict ended on July 11, 1921, and negotiations to conclude the Anglo-Irish Treaty began in December of that year.