La Salle meanwhile at Fort Miami was making new plans and resolutions. He had an idea of banding together under his leadership all the western tribes, and by this means to keep the Iroquois in check while he perfected his explorations southward. So in the spring (1681) he returned to the Illinois country to try to form the league; and while there first heard from some wandering Outagamies of the safe arrival of Tonty at Green Bay, and of the passage through that region of Hennepin eastward. Among the Illinois and on the St. Joseph he was listened to, and everything promised well for his intended league. In May he went to Michillimackinac, where he found Tonty and Membré, and with them he proceeded to Fort Frontenac. Here once more his address got him new supplies, and in the autumn (1681) he was again on his westward way. In the latter part of December, with a company of fifty-four souls,—French and savage, including some squaws,—he crossed the Chicago portage; and sledding and floating down the Illinois, on the 6th of February he and his companions glided out upon the Mississippi among cakes of swimming ice. On they went.[602] Stopping at one of the Chickasaw bluffs, they built a small stockade and called it after Prudhomme, who was left in charge of it. Again they stopped for a conference of three days with a band of Indians near the mouth of the Arkansas, where, on the 14th of March, in due form, La Salle took possession of the neighboring country in the name of his King.[603] On still they went, stopping at various villages and towns, securing a welcome by the peace-pipe, and erecting crosses bearing the arms of France in the open squares of the Indian settlements. On the 6th of April La Salle divided his party into three, and each took one of the three arms which led to the Gulf. On the 9th they reunited, and erecting a column just within one of the mouths of the river, La Salle formally took possession of the great Mississippi basin in the name of the French monarch, whom he commemorated in applying the name of Louisiana to the valley.[604]
Up the stream their canoes were now turned. On reaching Fort Prudhomme La Salle was prostrated with a fever. Here he stayed, nursed by Membré,[605] while Tonty went on to carry the news of their success to Michillimackinac, whence to despatch messengers to the lower settlements. At St. Ignace La Salle joined his lieutenant.