La Vérendrye built Fort St. Pierre, a small post on Rainy River. La Vérendrye next established a strong French foothold in the area at Fort St. Charles on what is now known as Magnuson's Island. From here, French-Canadian voyageurs explored a large section of mid-continent North America, constructed other forts, and conducted fur trading, whose revenues were critical to the economy of the colony. The "golden age" of the French-Canadian fur trade lasted for 30 years before they were forced to abandon their forts at the end of the French and Indian War in 1763. As a result, the area came under the jurisdiction of the British. Transfer of the area to the rule of the United States occurred at the conclusion of the American Revolutionary War when the Treaty of Paris was signed in 1783. The exact boundary was not established until 1842. This was due to confusion about the precise location of the "northwest corner of Lake of the Woods." After 50 years of controversy and confusion the matter was officially settled when the official boundary was established.