This article is about the Dutch fortress on the present-day Delaware River. For other settlements with the same name, see Fort Nassau (disambiguation).
The South River c. 1650.1891 USGS 1891 map showing the confluence of the Schuylkill and Delaware rivers, site of Dutch and Swedish fortsModern map showing some New Netherland settlements
Initially the fort was occupied intermittently, and on occasion used by the local population in seasonal migrations. In 1635, colonists from Virginia Colony occupied the fort. The governor of New Netherland at the time, Wouter van Twiller, sent a force and was successful in retaking the fort. This was the first of conflicts between the English and Dutch in the New World.[11][12] While thereafter the fort was continuously manned, the location was ill-suited to trade, as the richest fur-trapping areas were on the west side of the Delaware River.
OnTrinity Sunday in 1654, Johan Risingh, Commissary and Councilor to New Sweden Governor Lt. Col. Johan Printz, officially assumed his duties. He tried to expel the Dutch from the Delaware Valley and sent forces against Fort Casimir; the garrison surrendered. He renamed it as Fort Trinity (in Swedish Fort Trefaldighet). The Swedes now completely controlled their colony. On June 21, 1654, local bands of the Lenape met with the Swedes to reaffirm their ownership.
Peter Stuyvesant led a Dutch force which retook the fort on September 11, 1655. He renamed it as New Amstel (in Dutch Nieuw Amstel). Subsequently, Fort Christina also fell to the Dutch on September 15 and all New Sweden came under their control. The Dutch appointed John Paul Jacquet as governor, and made New Amstel the capital of the Dutch-controlled colony.[14][15]
^Rink, Oliver (2009). "Seafarers and Businessmen". Dutch New York: The Roots of Hudson Valley Culture. Yonkers, NY: Fordham University Press & Hudson River Museum. p. 20. ISBN978-0-8232-3039-6.
^Gehring, Charles T. (1995), "Hodie Mihi, Cras Tibi", New Sweden in America Swedish-Dutch relations in the Delaware Valley, University of Delaware Press, ISBN0-87413-520-6