Tancred

There is a similar story about the "Seven Cities of Cibola". No one has ever found them, but they were a nearly universal myth.
More realistically, when DeSoto made his epic journey from the Gulf Coast to the Midwest the Indians all along the way told him where the gold was.
When he finally got to Terre Haute (Pacaha's Town) and they pointed off toward Weedpatch Hill in Brown County (and to the Needmore/Trevlac area in Monroe County), his men avoided the high glacial hills to their North and went instead through West Baden Springs and came back with a wagon load of fools gold (iron pyrite and some other mineral crystals).
Later on gold miners found gold exactly where DeSoto had been told.
I've always found it remarkable that DeSoto's people didn't pay attention to this matter of going to exactly where the gold is - some of these fellows had worked with DeSoto's employee Pizarro and they certainly knew something about the matter.
Cabeza de Vaca was the first to describe America's Gulf Coast States. While in Houston (circled on the map), visiting Natives told Vaca of inland places, convincing him that wealthy tribes and an ocean were located to the north. Both Coronado's and DeSoto's Trails would lead to places north of Houston. Both reversed direction there. Spain would never return for another search for whatever Vaca privately told the two Conquistadors; nor did Vaca publish whatever he told them. England and France would continue searching for a Northern Sea passage to China for the rest of that Century, allowing the Spanish freedom elsewhere.

DeSoto traveled Florida, Georgia, North and South Carolina, Tennessee and Alabama on his way to waiting supply ships at Mobile, but lost all of his collected treasure in battle before he got there. Embarrassed, DeSoto fled due north through Tennessee, Kentucky and Indiana; his scouts as far as Chicago. Finding NO OCEAN there, DeSoto headed west thru Illinois, still seeking an ocean passage to China. Discovering the Mississippi River, which obviously drained a land mass much larger than DeSoto had surmised, must have been the worst day of DeSoto's life. No more dreams of trade with China. He headed southwest into Missouri searching for Vaca's fabled wealthy tribes. He wintered in Arkansas where he died of humiliation. His army headed southwest through Louisiana and Texas, scouts as far as San Antonio. Wanting food, all retreated back to Arkansas. They wintered building boats and conducting raids along the Arkansas River, part of the Great River. They drifted down that river, passing beside Mississippi, where Native raids were made, then thru Louisiana, then coasted Texas to Spanish Mexico.