But not for long, for at El Paso there gathered a force dedicated to revenge for their comrades who had died before the Indian onslaught. Ably led by Diego de Vargas, this expedition moved into New Mexico in 1692. The Indians, who had achieved such unity for the moment in 1680, were again badly divided. De Vargas, instead of having to subdue an alliance, had only to deal with one pueblo at a time. Very quickly New Mexico was returned to a mission area and frontier military post. The Pueblo Indians became permanently subjected to European domination. Their one and only attempt at unity had, in the final analysis, failed. During the seventeenth and eighteenth centuries, New Mexico was the heart of the Spanish empire in the Southwest. Only in southwestern Arizona, western Texas, and California did the Spanish hold any land other than in the upper Rio Grande Valley of New Mexico. During these centuries, this valley complex played out its dual role of mission area and military outpost. Its only connection with the resources and ideas of the world was a long hazardous road that stretched from Santa Fe to Chihuahua City and then south to Mexico City. This was New Mexico’s Royal Road, and over it moved everything needed by soldier, priest, and civilian. The trade was dominated by the merchants of Chihuahua, and New Mexico suffered. The tale of New Mexico during this period was one of poverty, hardship, and warfare. And several vital forces moved across the land. One of these forces had long been in the Southwest, but latent. The Spanish adopted an Indian word meaning _enemy_ to describe it—Apache! The Spanish brought with them domesticated animals which quickly adapted to conditions of the New World and became available to the Indian. Most important was the horse, at least as far as the Apache was concerned. By the early eighteenth century, the Apache, and other groups on the plains, had adapted to the use of the horse. While dangerous as foot soldiers, the Apache became vastly more dangerous as mounted warriors. Whereas they had been satisfied with minor raids against the pueblos and the Spanish holdings prior to 1700, they exploded on a wave of terrorism during the eighteenth century which very nearly drove the Spanish from the frontier. Late in the century, the conflict between the Apache and the Spanish became increasingly bitter. The history of the Southwest became the history of incessant Indian incursions and Spanish attempts to control the raiders. The missions declined and in many instances gave way entirely to the presidio or fort. In New Mexico the military came to dominate the missionary, and only through the heroic efforts of the meager force at the Presidio of Santa Fe did the Spanish manage to hold New Mexico from total collapse. A poor province became poorer, population declined, both among the Spanish and Indian, and the future looked dark indeed.