Complex sentence: French missionary Simon Bruté spent two decades as teacher and pastor in the formative years of Mount St. Mary's; he was considered "one of the foremost scholars in America", and he had a great deal of influence on the Catholic Church in America.
Split into simpler sentences: French missionary Simon Bruté spent two decades as teacher and pastor in the formative years of Mount St. Mary's. He was considered "one of the foremost scholars in America", and he had a great deal of influence on the Catholic Church in America.