Bancker was the son of Gerard Bancker Sr. and Maria de Peyster, who had married in
New York City in 1731. He was the grandson of
Johannes de Peyster (1666–1719), the 23rd
Mayor of New York City between 1698 and 1699, and great-grandson of
Johannes de Peyster, Sr., the Huguenot first settler of the De Peyster family in North America. Bancker was elected to the
American Philosophical Society in 1772, and in 1774, as city
surveyor, he made a map of St. George's Ferry on
Nassau Island. He was Deputy Treasurer from 1776 to 1778, and
New York State Treasurer from 1778 to 1798. He collected a large number of
broadsides from the revolutionary era which were sold at auction in 1898 in
Philadelphia. ==Notes==