Guilliam Cornelis, b abt 1600, son of a prosperous French merchant in Rotterdam. He migrated to New Amsterdam in 1640 with his eldest son, Guilliam (Willem) Guilliamse. His second son, Pierre (Pieter) Guilliamse followed in 1642. Guilliam Cornelis was a sea captain and he hired the "Oak Tree," a cargo vessel, in which he was skipper in 1641. He
died in 1667. He may have had a brother Pieter Cornelis, also a sea captain.