La Salle, fearing the influence of the stories among the Indians, upon his men, decided to separate from them and go further down the river where he could construct his fort and built his boat. On the evening of the 15th of January, 1680, La Salle moved to a point on the east side of the river three miles below the present site of Peoria. There on a projection from the bluffs he built with considerable labor a fort which received the name of Crevecoeur. This was the fourth of the great chain of forts which La Salle had constructed, namely: Fort Frontenac at the outlet of Lake Ontario; Fort Tonti on the Niagara River; Fort Miami at the mouth of St. Joseph River, and Crevecoeur below Lake Peoria on the Illinois River. Fort Crevecoeur is currently believed to have been so named because of the disheartened frame of mind of La Salle, but this would not be complimentary to the character of the man. It is now rather believed to have been so named in honor of Tonti, since as a soldier in the Netherlands he took part in the destruction of Fort Crevecoeur near the village of Bois le Due in the year 1672. In addition to the building of the fort, La Salle began the construction of a vessel with which to complete his journey to the mouth of the river. The lumber was sawed from the timber and rapid progress was made. The keel was 42 feet long, and the beam was 12 feet. While this work was in progress and during the month of February, several representatives of tribes from up the Mississippi and down the Mississippi, as well as from the Miamis to the northeast, came to consult with La Salle. His presence in the Illinois country was known near and far. The Indians from the upper Mississippi brought tempting descriptions of routes to the western sea and also of the wealth of beaver with which their country abounded.
La Salle desired to make a visit to Fort Frontenac for sails, cordage, iron, and other material for his boat, besides he was very anxious to hear something definite about the Griffin, and its valuable cargo. But before embarking on his long journey, he fitted out an expedition consisting of Michael Ako, Antony Auguel, and Father Hennepin, to explore the upper Mississippi. Michael Ako was the leader. They started February the 29th, passed down the Illinois River and thence up the Mississippi. They carried goods worth a thousand livres, which were to be exchanged for furs. Father Hennepin took St. Anthony for his patron saint and when near the falls which we know by that name, he set up a post upon which he engraved the cross and the coat of arms of France. He was shortly captured by the Indians and was later released by a French trader, De Lhut. He then returned to France.
Source: A Standard History of Champaign County, Illinois, by J. R. Stewart, published by The Lewis Publishing Company, Chicago And New York, 1918.