This was in the early summer of 1680. Luckily for Hennepin and his companions, the powerful _coureur de bois_, Daniel Graysolon Duluth (_du Luth_) appeared on the scene. Duluth was, next to Perrot, the leading man in the country around Lake Superior and the Upper Mississippi valley. He had been spending the winter trading with the Sioux in the lake country of northern Minnesota, and along Pigeon River, which is now the dividing line between Minnesota and Canada. With a party of ten of his boatmen, he set out in June to reach the Mississippi, his route taking him up the turbulent little Bois Brulé River, over the mile and a half of portage trail to Upper Lake St. Croix, and down St. Croix River to the Mississippi. On reaching the latter, he learned of the fact that Europeans were being detained and maltreated by the Sioux, and at once went and rescued them. The summer was spent among the Indians in company with Hennepin's party, who, now that Duluth was found to be their friend, were handsomely treated. In the autumn, Duluth, Hennepin, and their companions all returned down the Mississippi, up the Wisconsin, and down the Fox, and spent the winter at Mackinac. After that, Duluth was frequently upon the Fox-Wisconsin route, and traded for buffalo hides and other furs with the Wisconsin tribes. Another famous visitor to Wisconsin, in those early days, was Pierre le Sueur, who in 1683 traveled from Lake Michigan to the Mississippi, over the Fox-Wisconsin route, and traded with the Sioux at the Falls of St. Anthony and beyond. His fur trade grew, in a few years, to large proportions; for he was a shrewd man, and was related to some of the officials of New France. This enabled him to secure trading licenses for the Western country, and other valuable privileges, which gave him an advantage over the unlicensed traders, like Duluth, who had no official friends. In 1693, Le Sueur was trading in Duluth's old country; and, in order to protect the old Bois Brulé and St. Croix route from marauding Indians, he built a log fort at either end, one on Chequamegon Bay, and the other on an island in the Mississippi, below the mouth of the St. Croix. A few years later, Le Sueur was in France, where he obtained a license to operate certain "mines of lead, copper, and blue and green earth," which he claimed to have discovered along the banks of the Upper Mississippi. In the summer of 1700, he and his party opened lead mines in the neighborhood of the present Dubuque and Galena, and also near the modern town of Potosi, Wisconsin. He does not appear to have been very successful as a miner; but his fur trade was still enormous, and his many explorations led to the Upper Mississippi being quite correctly represented on the maps of America, made by the European geographers.