Complex sentence: He then acted on a call he felt to the priesthood and, due to his limited formal education, enrolled in St. Francis High School Seminary, the minor seminary of the Archdiocese of Milwaukee at the age of 21, hoping to become a diocesan priest.
Split into simpler sentences: He then acted on a call he felt to the priesthood. Because of his limited formal education, he enrolled at St. Francis High School Seminary, the minor seminary of the Archdiocese of Milwaukee at age 21, hoping to become a diocesan priest.