Roman Catholic Cardinal. A native of Tarquinia, following his studies at the interdiocesan seminary of Montefiascone, the seminary of Viterbo and the Pontifical Roman Seminary, Sergio Guerri was ordained priest in March 1929. Furthering his studies at the Pontifical Lateran Athenaeum and the Pontifical Roman Athenaeum of S. Apollinare, he served as administrator of the Pontifical Urbanian Athenaeum De Propaganda Fide from 1937 until 1941. Named privy chamberlain of His Holiness on April 11, 1940, Guerri served as official of the Institute for Works of Religion between 1941 and 1946 and successively as its substitute secretary from 1946 till 1948. Appointed pro-secretary of the Administration of the Patrimony of the Holy See on March 9, 1948 and secretary of the cardinalitial commission for the Administration of the Patrimony of the Holy See on January 1, 1951, he was named canon of the Patriarchal Vatican Basilica on April 25, 1952. Appointed secretary of the administrative secretariat for the preparation of the Second Vatican Council on June 22, 1960, he acted as delegate for the Special Administration of the Holy See and administrative secretary of the Second Vatican Council. Secretary of the Administration of the Patrimony of Holy and pro-president 'ad interim' of the Pontifical Commission for the State of Vatican City, Pope Paul VI elected him archbishop of the titular see of Trevi, receiving his episcopal consecration on April 27, 1969, at the chapel of the Lateran Seminary from Cardinal Amleto Giovanni Cicognani. The very next day, the named Pope created him cardinal, receiving the deaconry of Ss.mo Nome di Maria al Foro Troiano two days later. Confirmed as pro-president of the Pontifical Commission for the State of Vatican City, Guerri opted for the order of cardinal priests, with his deaconry elevated pro illa vice to title on June 30, 1979. Retiring from office on September 26, 1981, he spent his remaining years at Vatican City, where he passed away aged eighty six. After learning the news of his death, Pope John Paul II visited his Vatican apartment to pray before his body. Transferred to his native Tarquinia, his body was originally interred in the local cemetery inside the family chapel, until being removed to a specially constructed crypt in the city's Annunziata church.