Complex sentence: Bulkeley later served one term in the U.S. Senate from 1905-1911 and was one of the seven members of Al Spalding's Mills Commission, the group that gave credence to the myth that Abner Doubleday invented baseball.
Split into simpler sentences: Bulkeley later served one term in the U.S. Senate from 1905 to 1911. He was also one of the seven members of the Mills Commission formed by Albert Spalding, the group that gave credence to the myth that Abner Doubleday invented baseball.