Spain claimed Texas on account of Columbus' discovery of America. King Louis granted (1712) all rights of Louisiana trade to Crozat. In spite of Spain's strict laws against trading with other nations, Crozat and his friends persuaded certain Spanish priests to allow them to trade in Texas, provided the French aided the Holy Fathers in establishing missions. The French Saint, Dimas led a trading expedition across Texas to the Rio Grande; this aroused Spain and caused her in 1716 to found six missions in East Texas; from this time, Texas was never without Spanish settlements. Spain's purpose was to convert the nations to Christianity, and to hold the territory for the king. The moral condition of the Indians made the task of the priests most difficult. The priests began with simple arbors and wooden buildings, worked patiently and persistently until they had trained the savages to labor so they could erect stone missions. The most interesting of missions was in and near San Antonio. Moses Austin, from Missouri came to San Antonio in 1820. Aided by Baron de Bastrop, he obtained permission from the Mexican government to settle 300 families in Texas. After the death of Moses Austin, his son Stephen located his grant of land on the lower course of the Brazos and the Colorado. Generous offers of land attracted many colonists. A revolution forced Austin to go to the City of Mexico (1822); in a year he returned after a special law had been passed by the Mexican congress, regulating matters in his colony. He was granted the right to settle 1,200 families and was the leading figure in the whole colonial era.