History of the Vatican By gosuzyn May 13, 1871 Italian Law after unification abrogated the power of the Pope May 13, 1871 Feb 11, 1929 Lateran Treaty Feb. 11, 1929 Oct 11, 1962 Vatican II Oct. 11, 1962 Modernization Aug 26, 1978 John Paul I Aug. 26, 1978 Oct 16, 1978 Cardinal Karol Wojtyla became John Paul II