Career
He was an Orangist, which means that he was a supporter of Prince William V of Orange. He became grand pensionary of Holland when the Prussian army had reinstated William V in power in 1787. He fled to Germany in 1795, when the French defeated the Dutch army and an anti-orangist revolution broke out.
He died in Lingen, Prussia.
Van de Spiegel was the last Grand Pensionary of the Republic of the Seven United Netherlands, which was replaced with the Batavian Republic modelled after the French revolutionary state. Laurens Pieter van de Spiegel was married to Digna Johanna Ossewaarde (1841–1813).
Cornelis was ennobled by King William I in 1815.