Sinn Féin then declared the Irish Republic to be in existence. Its parliament, the First Dáil, first met in January 1919, and the British declared it an illegal assembly shortly afterwards. At around the same time, the Volunteers, now organised as the Irish Republican Army began a guerrilla war, the Irish War of Independence (1919–1921), against the British Government in Ireland. By July 1921, the campaign had brought the British Government to the conclusion that it would have to negotiate with the Dáil to end the violence.