Hernando de Soto 

Hernado De Soto was born in Spain.  That was the same country that founded his voyage as well.  On one trip he he went to "The New World" to find gold. He sailed to Florida. When he did not find gold,he moved on. He wandered the lower pennisula for 3 years.  They wandered Georgia, part of North and South Carolina, Mississippi and Tennessee and eventually he came to the mississippi river. Only months later he became sick and died of a fever.  The crew feared they were going to be conqured.  So they threw his body into the Mississippi river.His crew went back to Spain and told the bad news. But De Soto was credited for finding the Mississippi river. 

SOURCES:

 USA studies weekly vol. 5 issue 1 week 5  publisher: American Legacy , 2007

 Harcourt Horizons publisher; Harcourt New York, 2003 

 http://go.grolier.com/