Who established a series of Spanish settlements in the Rio Grande valley

In the course of establishing his fort, La Salle undertook two expeditions into the interior of Texas, one of which reached the Río Grande somewhere between Del Río and Eagle Pass. Unsettled by the threat, the Spaniards quickly began a series of land and sea expeditions to locate and destroy the French position.

Explanation:

logging hope this

the crusaders are identified in the painting;

c. by the red crosses on their backs