Complex sentence: It is a Private-Catholic school established by the Missionary Society of Saint Columban (MSSC) in 1940 but was turned over to the Diocese of Pagadian in the 1960's.
Split into simpler sentences: It is a private catholic school established by the Missionary Society of Saint Columban (MSSC) in 1940. The management of the school was turned over to the Diocese of Pagadian in the 1960's.