He spent about one year in exploring the country bordering on the lakes, and in selecting positions for forts and trading posts, to secure the Indian trade to the French. After he had built a fort at Niagara, and fitted out a small vessel, he sailed through the lakes to Green bay, then called the "Bay of Puants." From thence he proceeded with his men in canoes towards the south end of lake Michigan, and arrived at the mouth of the "river of the Miamis" in November, 1679. This is thought to be the Milwaukee in Wisconsin Territory. Here he built a fort, left eight or ten men, and passed with the rest of his company across the country to the waters of the Illinois river, and descended that river a considerable distance, when he was stopped for want of supplies. This was occasioned by the loss of a boat which had been sent from his post on Green bay. He was now compelled by necessity to build a fort, which, on account of the anxiety of mind he experienced, was called Creve-cœur, or broken heart.

The position of this fort cannot now be ascertained; but from some appearances, it is thought to have been near Spring bay, in the northeast part of Tazewell county.

At this period the Illinois were engaged in a war with the Iroquois, a numerous, warlike, and cruel nation, with whom La Salle had traded, while on the borders of Canada. The former, according to Indian notions of friendship, expected assistance from the French; but the interests and safety of La Salle depended upon terminating this warfare, and to this object he directed his strenuous efforts. The suspicious Illinois construed this into treachery, which was strengthened by the malicious and perfidious conduct of some of his own men, and pronounced upon him the sentence of death. Immediately he formed and executed the bold and hazardous project of going alone and unarmed to the camp of the Illinois, and vindicating his conduct. He declared his innocence of the charges, and demanded the author. He urged that the war should be terminated, and that the hostile nations should live in peace.

The coolness, bravery, and eloquence of La Salle filled the Indians with astonishment, and entirely changed their purposes. The calumet was smoked, presents mutually exchanged, and a treaty of amity concluded.

The original project of discovery was now pursued. Father Hennepin started on the 28th of February, 1680, and having passed down the Illinois, ascended the Mississippi to the falls of St. Anthony. Here he was taken prisoner, robbed, and carried to the Indian villages, from which he made his escape, returned to Canada by the way of the Wisconsin, and from thence to France, where he published an account of his travels.

La Salle visited Canada to obtain supplies, returned to Creve-cœur, and shortly after descended the Illinois, and then the Mississippi, where he built one or two forts on its banks, and took possession of the country in the name of the king of France, and in honor of him called it Louisiana.

One of these forts is thought to have been built on the west side of the river, between St. Louis and Carondalet.

After descending the Mississippi to its mouth, he returned to the Illinois, and on his way back left some of his companions to occupy the country. This is supposed to have been the commencement of the villages of Kaskaskia and Cahokia, in 1683. La Salle went to France, fitted out an expedition to form a colony at the mouth of the Mississippi, sailed to the gulf of Mexico, but not being able to find the mouths of that river, he commenced an overland journey to his fort on the Illinois. On this journey he was basely assassinated by two of his own men.[3]

After the death of La Salle, no attempts to discover the mouth of the Mississippi were made till about 1699, but the settlements in the Illinois country were gradually increased by emigrants from Canada.

In 1712, the king of France, by letters patent, gave the whole country of Louisiana to M. Crosat, with the commerce of the country, with the profits of all the mines, reserving for his own use one fifth of the gold and silver. After expending large sums in digging and exploring for the precious metals without success, Crosat gave up his privilege to the king, in 1717. Soon after, the colony was granted to the Mississippi company, projected by Mr. Law, which took possession of Louisiana, and appointed M. Bienville governor. In 1719, La Harpe commanded a fort with French troops, not far from the mouth of the Missouri river.