Van Cortlandt, Jacobus (jəkōˈbəs văn kôrtˈlənd) [key], 1658–1739, colonial American merchant, b. New Amsterdam (later New York City); brother of Stephen Van Cortlandt. He served (1710 and 1719) as mayor of New York. He purchased land in Yonkers and was thus founder of the estate that was bought (1899) by New York City and converted into Van Cortlandt Park, a tract of 1,132 acres (459 hectares). The manor house in the park was built by Jacobus's son Frederick in 1748.