Complex sentence: The doors to the original lecture room on the north end of the first floor were made of solid oak, and the tiered seating of the room could hold 500 people, housing the largest classes on campus, specifically English, history and botany classes.
Split into simpler sentences: The doors to the original lecture room on the north end of the first floor were made of solid oak, and the tiered seating of the room could hold 500 people. The original interior held a 500-seat auditorium, housing the largest classes on campus, specifically English, history and botany classes.