 The pro-Treaty side included members of the old IRA who had fought the British during the recent Irish War of Independence.Led by Michael Collins and Richard Mulcahy, it soon became the nucleus of the new (regular) Irish National Army that overcame their anti-Treaty IRA opponents during the often bitter Irish Civil War of 1922–23.The term is sometimes heard anachronistically in Northern Ireland for anyone from the South of the country, occasionally as a pejorative term.