Jacques Marquette (1636-75) was a French Jesuit who, on completion 
of his training in 1666, was sent to Quebec where he studied Indian 
languages.  Four years later he was sent as a missionary to the 
Ottawa Indians, and remained with them when they fled from the 
Sioux and resettled in Mackinac.  There he founded a mission on 
Point St. Ignace.  In 1672, Louis Joliet, a former Jesuit, arrived with 
orders for Marquette to explore the region south of Lake Michigan.  
Joliet and Marquette set off in May of 1673 and with the help of 
Indian guides, charted the Mississippi River as far south as the 
Arkansas River, where they turned back, fearing capture by the 
Spanish.  The 2,900-mile, round-trip journey proved too strenuous 
for Marquette, who died on the return to St. Ignace.