Grand Pensionary of Holland from 17 July 1727 to 1 December 1736. Before becoming grand pensionary Van Slingelandt wrote several reports as preparation for the second Great Assembly (Dutch Tweede Grote Vergadering, a kind of Constitutional Convention to reform the constitution of the Dutch Republic, 28 November 1716 – 14 September 1717), in which he proposed to give the Council of State ("Raad van State") more power.
