JANSEN VAN ILPENDAM, Jan, Dutch official, died probably at Marcus Hook, Pennsylvania, in 1685. About 1640 he was appointed by Governor William Kieft custom-house officer on the Delaware, and put in command of Fort Nassau. In 1642 a company from New Haven attempted to effect a settlement nearly opposite the fort, to prevent which Jansen was ordered by the Dutch governor to proceed to the unbidden comers and require of them to show by what "authority they acted, and how they dared to make such encroachment on our rights and privileges, our territory and commerce; and, if they could show no authority, to let them depart, and, if they refused, to take them prisoners and bring them to New York"; and to aid him in enforcing his authority he was sent two yachts, and directed to man them. This order he obeyed, and it resulted in his burning the trading-house and taking the traders prisoners, whereat the government of New Haven addressed to Kieft a vigorous protest. In 1644 he refused to allow a Boston company to pass up the river on the ostensible mission of exploring for the Syconian lake. In 1645 he fell into disfavor, and was charged with fraud and neglect of duty in his office as commissary of the fort, one item of his offending being that he had given "more to the Indians than the ordinary rate." He was removed, and Andreas Hudde appointed to succeed him. He continued to reside on the river and to trade with the Indians, and is frequently named in historical documents.