Complex sentence: Upon his graduation, he and his maternal aunt, Helen Hartley (Mrs. George W.) Jenkins presented the Hartley Hall dormitory to Columbia, which became its largest dormitory and created more of a college atmosphere for the new campus in Morningside Heights.
Split into simpler sentences: Upon his graduation, he and his maternal aunt, Helen Hartley (Mrs. George W.) Jenkins presented the Hartley Hall dormitory to Columbia. The building became its largest dormitory and created more of a college atmosphere for the new campus in Morningside Heights.