Complex sentence: Robert van Rensselaer was born December 16,1740, at Fort Crailo in Rensselaer, New York to Johannes Van Rensselaer (1708--1793), and Engeltie "Angelica" Livingston (1698--1746/47).
Split into simpler sentences: Robert Van Rensselaer was born December 16,1740, at Fort Crailo in Rensselaer, New York. He was the son of Johannes Van Rensselaer (1708--1793), and Engeltie "Angelica" Livingston (1698--1746/47).