On 24 April 1916 the Easter Rising began. De Valera occupied Boland's Mills, Grand Canal Street in Dublin. After the fighting de Valera was court-martialled, convicted, and sentenced to death, but the sentence was changed to for life imprisonment. This was because he was not kept in Kilmainham Jail with the first prisoners executed. The delay meant British authorities started to check if he really was an American citizen, and wonder how the United States would react to the execution of one of its citizens.