According to the Internet source given below, Carolus Hacquart was a Netherlands musician and composer. He was a much-praised player of viol, lute and organ, who also wrote Latin sacred works and, in 1678, the music for the first Netherlands opera. Amongst his most important works are the ten trios and quartet sonatas in Harmonia Parnassia (1686).

Websites:
	Carolus Hacquart	Brief biography by HOAS.