Answer:
In the beginning, most of the territory of the Middle colonies were a part of New Netherland, the Dutch colony that existed in the 17th century. Modern territories of Delaware, New Jersey, New York, and Pennsylvania comprised the Middle colonies.
English were involved in several conflicts with Dutch in order to take control of these territories. As a result of the Second Anglo-Dutch War (4 March 1665 – 31 July 1667), English conquered most of the given land and, in particular, the city of New Netherland. If this would not happen, Modern New York would still bear the name New Netherland. The city was renamed after the Duke of York.
