Who was the french explorer the spanish worried about?

René-Robert Cavelier, Sieur de La Salle

Explanation:

better known as Robert de La Salle, was a French explorer best remembered for sailing the length of the Mississippi River and claiming the lands around it for France, thus creating the territory of Louisiana, which he had named La Louisiane after King Louis XIV.

René-Robert Cavelier, Sieur de La Salle

Explanation:

René-Robert Cavelier, Sieur de La Salle was a 17th-century French explorer and fur trader in North America. He explored the Great Lakes region of the United States and Canada, the Mississippi River, and the Gulf of Mexico.