Complex sentence: In 1855 he went to Delaware College, where he filled the same position, but in 1869, he returned to the University of Pennsylvania as professor of comparative philology and remained there until his death, which occurred at Chickies, Pennsylvania.
Split into simpler sentences: In 1855 he went to Delaware College, where he filled the same position, but in 1869, he returned to the University of Pennsylvania as professor of comparative philology. Haldeman remained there until his death, which occurred at Chickies, Pennsylvania.