Complex sentence: He had issue, a son and a daughter, but his son (1737--1740) died in infancy, and his daughter (1739--1758) from smallpox at the age of 19.
Split into simpler sentences: He had issue, a son and a daughter. His son (1737--1740) died in infancy, and his daughter (1739--1758) from smallpox at the age of 19.