Complex sentence: A year later Harcourt became Lee's Reader in chemistry and took a position as a senior student at Christ Church, Oxford, where he was a contemporary of Charles Dodgson, better known as Lewis Carroll, and is mentioned in Carroll's diaries.
Split into simpler sentences: A year later Harcourt became Lee's Reader in chemistry and took a position as a senior student at Christ Church, an Oxford college. Harcourt was contemporary with Charles Dodgson, better known as Lewis Carroll, and is mentioned in Carroll's diaries.