The first fort on the Straits of Mackinac, Fort Du Buade, was constructed in about 1690 by the French near the St. Ignace Mission on the north side of the Straits of Mackinac. It was closed in 1697. By the early 1700s the French began to refortify the area. In 1715 they constructed Fort Michilimackinac on the south side of the Straits (present day Mackinaw City ). The fort became the main trade depot of the upper Great Lakes fur trade. The fort functioned as both a military post and a civilian community. Michilimackinac remained a French outpost until 1761 when British soldiers took control after their victory in the French and Indian War (Seven Years War).