Complex sentence: He became senior bursar of his college in 1825, and during a long tenure of the office, only resigning it when he left Cambridge in 1837, his sound judgment and practical knowledge of business proved of great service.
Split into simpler sentences: He became senior bursar of his college in 1825, and during a long tenure of the office only resigning it when he left Cambridge in 1837. His sound judgment and practical knowledge of business proved of great service.