Complex sentence: The Reverend Dr Nevil Maskelyne (1732--1811) who was, in 1765, appointed as the Astronomer Royal, was a noteworthy member of this family who were involved in Purton life for over four centuries from the 1500s.
Split into simpler sentences: The Reverend Dr Nevil Maskelyne (1732--1811) was appointed Astronomer Royal in 1765. The Maskelynes were involved in Purton life for more than four centuries from the 1500s.