NUEVO SANTANDER. The Spanish province of Nuevo Santander, comprising the present Mexican state of Tamaulipas and part of trans-Nueces Texas, was founded by José de Escandón and named for his native province in Spain. Designated a province by viceregal order of September 3, 1746, the region was explored the following year by units converging from Texas, Coahuila, and Nuevo León, as well as those from Querétaro under Escandón's personal leadership. With actual settlement begun late in 1748, it was the last part of northeastern Mexico to be conquered and effectively occupied. Despite the lateness of its beginning, the Nuevo Santander population soon outpaced that of Texas, reaching 30,000 by the end of the century. The colony, initially called Colonia de la Costa del Seno Mexicano (“Gulf Coast colony”), grew from a series of proposals by Nuevo León governors and others for controlling the hostile Indians who took refuge in the coastal jungle and adjacent mountains. For more than two centuries the territory had been held by “indios bárbaros, pagans, and apostates.” These natives, many of whom had suffered from Spanish slave raids and oppression in the haciendas, had resisted the inroads of Christianity and civilization, afflicting shipwreck castaways as well as settlers. Not only had they denied Spain the economic benefits of ports, salt deposits, and agricultural lands, but they had forced travelers between Mexico City and La Bahía, on the Guadalupe River in Texas, to take a route twice the shortest distance.
Full article on the Texas State Historical Association's Handbook of Texas Online