Complex sentence: Johnson married Mary Watts (daughter of John Watts of New York) on 30 June 1773 and the couple had eight sons, all of whom served in the British army and navy, and three daughters.
Split into simpler sentences: Johnson married Mary Watts (daughter of John Watts of New York) on 30 June 1773. The couple had eight sons, all of whom served in the British army and navy, and three daughters.