The Comanches and other forces conspired to force a Spanish retrenchment and realignment on the frontera. In 1776, the crown established the Commandency General of the Internal Provinces of the North in order to deal with Apache marauders in northern Mexico, Comanches on the plains, as well as to counter British ambitions on the Mississippi and the Gulf. When American colonists rebelled in 1775, the Spanish watched and waited, making their move in 1779 to seize British holdings on the east bank of the Mississippi.
Comanche fortunes, meanwhile, plummeted. Plains trade dried up because of the American Revolution and what had been amicable trade with the Kiowas and Pawnees turned to war in 1780. In 1781 a continent wide smallpox epidemic killed half of the Comanches, hitting the eastern bands the hardest.
The world changed in 1783. That year, the Treaty of Paris ensured the independence of a new nation, the United States of America. The Spanish, having gained back Florida during the war just ended, now sought a permanent peace with the Comanches in order to cultivate them as a barrier to American ambitions. To do so, they dispatched Pedro Vial in 1785 to seek an audience with the Comanches. Chiefs Camisa de Hierro (Iron Shirt) and Shaved Head, eastern Comanches, agreed to terms, as did Ecueracapa, chief of the Western Comanches.
The Numunu, once in control of the southern plains, had to retrench as well.