Complex sentence: His papacy was during the time when Egypt was part of the Ottoman Empire and was ruled by consecutive short-term (2--3 years each) representatives of the sultan and the church was under much pressure from the rulers.
Split into simpler sentences: His papacy was during the time when Egypt was part of the Ottoman Empire. Egypt in that time was ruled by consecutive short term (2--3 years each) representatives of the Sultan and the church was under a lot of pressure from the rulers.