Complex sentence: On March 4,1821, he was elected to the US Senate, and he served there until his death in Boardman, Ohio during a visit to his son, whereupon he was succeeded by Henry W. Edwards.
Split into simpler sentences: On March 4,1821, he was elected to the US Senate. He served there until his death in Boardman, Ohio during a visit to his son, whereupon he was succeeded by Henry W. Edwards.