La Salle's first appearance on Lake Michigan was in September, 1679, six years after Joliet's expedition. La Salle came down through the Straits of Mackinac with a party of seventeen, skirted the western shore of the lake toward the south, but believing he could reach the Illinois River by a more favorable route than that over which Joliet had passed, he coasted around the southern end of the lake until he reached the mouth of the St. Joseph River. Ascending that river he found the portage into the Kankakee and readily made his way to the Illinois, where he established a fort near Peoria. He returned to Canada the following year, and recruiting another party he once more passed over the St. Joseph-Kankakee route to the same destination as before. Again returning to Canada he started near the end of the year 1681 with a much larger party, and this time he chose the Chicago-Desplaines route to the interior. He continued on down the Illinois to its mouth, thence down the Mississippi, passed the farthest point reached by Joliet, and at length arrived at its mouth and issued forth upon the waters of the Gulf of Mexico. This event took place on the 7th of April, 1682. La Salle was thus the first white man to pass down the Mississippi River from the mouth of the Illinois to the Gulf. De Soto's followers after his death had indeed returned from their ill-starred expedition by way of the lower Mississippi, but it remained for La Salle to arrive at a certain knowledge of the course taken by the river throughout the long distance over which he passed and to determine its flow into the Gulf of Mexico, and moreover to establish the first substantial claim in behalf of a European power to the soil of Louisiana. La Salle had entered upon an extensive system of colonization, and through many dangers and difficulties he had secured footholds for the French in the western country. He passed frequently back and forth between the forts he had established and his base of supplies at Montreal. In the summer of 1683 he was in Chicago and wrote a letter to his lieutenant, Tonty, whom he had left in command of Fort St. Louis, on the Illinois River, dating the letter "Portage du Chicagou, 4 Juin, 1683." During the next three years he spent the larger part of his time in attempting to found a colony on the shores of the Gulf of Mexico, and while in the midst of his activities he was foully assassinated by some of his followers. His death occurred on March 19, 1687.