Complex sentence: On 18 September 1708, Pieter Willem married 17-year-old Magtilt van der Merwe, the daughter of Willem Schalkzoon van der Merwe and Elsie Cloete.
Split into simpler sentences: On 18 September 1708, Pieter Willem married the 17-year-old Magtilt van der Merwe. The daughter of Willem Schalkzoon van der Merwe and Elsie Cloete.