Publication of Summi Pontificatus

Date: October 20, 1939 • Location: Rome, Italy

Pope Pius XII (pictured) published his first encyclical, Summi Pontificatus, which critiqued ideologies such as racism, cultural superiority and totalitarianism.

Pope Pius XII was head of the Catholic Church and sovereign of the Vatican City from 2 March 1939 until his death in 1958. His pontificate spanned World War II, the Holocaust, and the first years of the Cold War. He is the most recent Pope to take the name Pius.