I am currently reading a book titled Mt. Lookout - "where you can see for two days" by Ruth Marie Coleville 1995. The book is about the Rio Grande, San Luis Valley and a town named Del Norte. Below is from the book.
"Now let's leave the mythic past and see how chance brought the first Europeans to meet the Great River. In the year 1519, only 27 years after Columbus discovered the new world (new to Europeans) four small Spanish ships were following a great unkown curve of land. It was the southern shore of North America, embracing what we call the Gulf of Mexico.
The ships had set out from Jamaica for Mexico, had been run out of the harbor by newly founded Vera Cruz by a fellow-countryman, Hernando Cortez, who wanted no competition. The little flotilla, now sailing an unknown coastline, came upon a place on the shell-white shore where a large river entered the sea. To the astounded Indians living there, the ships were four houses on the water, trees with wings growing on them.
Captian Alonzo Alvarez de Pineda, commander of the little fleet, approched the shore in a small boat, grounded, and stepped in the surf. With ceremony he slashed the blade of his sword into the waves, proclaiming, as was the custom of Europeans during the free-for-all centuries, that these waters, this land, and all in the province was possessions of His Most Catholic Majesty, the King of Spain.
The explorers stayed about 40 days, scraping barnacles and repairing the ships. The air was balmy, the Indians friendly. They traded with the Indians and explored eighteen miles up the river whose course was marked by palm trees, and then departed for Jamaica. They were the first Europeans to see the Rio Grande. They named the river of their pleasant experience, Rio de las Palmas, Palm River".
Would be cool if your coin was that old.