Complex sentence: He began studying at the Pontifical Ecclesiastical Academy in 1952 and joined the Vatican diplomatic service, section of Extraordinary Ecclesiastical Affairs, Secretariat of State, in 1953; in charge of affairs of Vietnam, China, Indonesia, and Southeast Asia in general.
Split into simpler sentences: He began studying at the Pontifical Ecclesiastical Academy in 1952 and joined the Vatican diplomatic service, section of Extraordinary Ecclesiastical Affairs, Secretariat of State, in 1953. He was in charge of affairs of Vietnam, China, Indonesia, and Southeast Asia in general.