Outposts along the Delaware c. 1650

In the early 1600s, a colonial conflict in miniature was waged along the Delaware River, with Dutch, Swedish and English participation. The Dutch staked the first claim. Fort Nassau (1623) was, with Fort Orange further north on the Hudson River, one of their first footholds in New Netherland. In 1638, the Swedes (under the Dutch ex-governor of New Amsterdam) established Fort Christina. The Swedes then set up Nya Elfsborg, yet further downstream, in a malarial swamp, and so soon abandoned. The English built a blockhouse (a type of crude fort) opposite Nassau in 1642; in the same year, a group of English colonists who had migrated from New Haven were discovered by the Dutch near the estuary and expelled. In 1651 the Dutch built Fort Casimir just 7 miles (12 km) south of Fort Christina, from which they threatened the Swedes. The denouement came in 1655, when a Dutch flotilla commanded by Peter Stuyvesant laid siege to Fort Christina, and ended the brief existence of New Sweden.