Complex sentence: He remained an employee and later a partner of Boulton & Watt until the 1830s, and his reputation as an inventor has been obscured by the reputations of Bolton and Watt and the firm they founded.
Split into simpler sentences: He remained an employee and later a partner of Boulton & Watt until the 1830s. His reputation as an independent inventor has tended to be obscured by the reputations of those two men and the firm they founded.