Original: Pope Pius XII ( ; ) , born Eugenio Maria Giuseppe Giovanni Pacelli ( 2 March 1876 -- 9 October 1958 ) , reigned as the 260th Pope , head of the Roman Catholic Church and sovereign of Vatican City , from 2 March 1939 until his death in 1958 .
Simplified: XII ) , born Eugenio Maria Giuseppe Giovanni Pacelli ( March 2 , 1876 -- October 9 , 1958 ) , was the 260th pope from March 2 , 1939 until his death in 1958 .