(born Eugenio Maria Giuseppe Giovanni Pacelli, ; 2 March 18769 October 1958) head of the Catholic Church and sovereign of the Vatican City State from 2 March 1939 until his death in October 1958.

The papacy of Pius XII (Eugenio Pacelli) began on 2 March 1939 and continued to 9 October 1958, covering the period of the Second World War and the Holocaust, during which millions of Jews were murdered by Adolf Hitler's Germany.

Several authors have alleged that there was a plot to kidnap Pope Pius XII by the Nazis when they occupied Rome during World War II.

The liturgical reforms of Pope Pius XII took place mostly between 1947 and 1958.