Complex sentence: The sports teams were known at the "Rough Riders" until the 70's, when after the reorganiztion of the school fater the closure of Paterson Colegiate, it became the "Trojans".
Split into simpler sentences: The sports teams were known at the "Rough Riders" until the 70's. With the closure of Paterson Colegiate, and re-organization of the school, it became the "Trojans".