Complex sentence: Caleb Rice (1792--1873) was an American politician and businessman, the first Mayor of Springfield, Massachusetts when it became a city in 1852, and also the first president of MassMutual Life Insurance Company, now a Fortune 100 company.
Split into simpler sentences: Caleb Rice (1792--1873) was an American politician and businessman. He was the first Mayor of Springfield, Massachusetts when it became a city in 1852, and the first president of MassMutual Life Insurance Company, now a Fortune 100 company.