The Dutch were the first Europeans to settle in present day Delaware by establishing a trading post at Zwaanendael, near the site of Lewes in 1631. Within a year all the settlers were killed in a dispute with Native Americans. In 1638 a Swedish trading post and colony was established at Fort Christina (now in Wilmington) by the Dutchman Peter Minuit at the head of a group of Swedes, Finns and Dutch. Thirteen years later the Dutch, reinvigorated by the leadership of Peter Stuyvesant, established a new fort in 1651 at present day New Castle, and in 1655 they took over the entire Swedish colony, incorporating it into the Dutch New Netherlands.
Only nine years later, in 1664, the Dutch were themselves forcibly removed by a British expedition under the direction of James, the Duke of York. Fighting off a prior claim by Cćcilius Calvert, 2nd Baron Baltimore, Proprietor of Maryland, the Duke passed his somewhat dubious ownership on to William Penn in 1682. Penn badly wanted an outlet to the sea for his Pennsylvania province and leased what were now known as the "Lower Counties on the Delaware" from the Duke.
Penn established representative government and briefly combined his two possessions under one General Assembly in 1682. However, by 1704 the Province of Pennsylvania had grown so much, their representatives wanted to make decisions without the assent of the Lower Counties and the two groups of representatives began meeting on their own, one at Philadelphia, and the other at New Castle. Penn and his heirs remained the Proprietors of both and always appointed the same person Deputy Governor for their Province of Pennsylvania and their territory of the Lower Counties.