The document discusses the history of the Irish Republican Army (IRA) and key events in Northern Ireland's sectarian conflict. It mentions the IRA's split into opposing factions during the Irish War of Independence and Irish Civil War in the early 20th century. It also summarizes violent attacks committed by the IRA such as Bloody Sunday and Bloody Friday in 1972 that killed and injured many civilians in Northern Ireland. The document provides sources for further information on the IRA and related topics.