What did Louis Jolliet accomplish?

Answer 1

Louis Jolliet, the French-Canadian explorer, went through Lake Michigan to Green Bay, then followed the Fox River, through marshes, to the Wisconsin River. From the point of the later settlement of Portage, he continued exploring until he entered the Mississippi River near Prairie du Chien, meaning Jolliet was the first to explore and map the Mississippi River for Europe (obviously Native Americans had "discovered" the river previous to him). After mapping several hundred miles, Jolliet stopped within 500 miles of the Gulf of Mexico, where he turned back at the mouth of the Arkansas River. They followed the Mississippi back north and learned from local natives of the Illinois River, which was a shorter route back to the Great Lakes. He had turned back for fear of meeting other (Spanish in particular) European explorers.

Answer 2

Nothing. He did nothing because he was to old and lazy to do anything so he hierd other people to do the sailing for him, and he took all of the credit.