The Spanish began to travel west of the conquered mainland of Mexico in the 16th century. These excursions were primarily in search of the mythicized island of gold. Hernán Cortés devised the first investigative voyage in 1532 and sent two fleets in search of the fabled island. When the unlucky ships returned, Cortés determined to lead the quest himself and found himself north of La Paz, near the south of the Baja California peninsula, in 1535. Although Cortés discovered a wealth of black pearls, his hopes for an island laden with gold were thwarted. Cortés retreated to mainland Mexico for a short while before entrusting another expedition to the command of Captain Francisco de Ulloa in 1539.

On this trip, Ulloa and his crew discovered more of the geology of the area as they traversed the full measure of the Sea of Cortés and identified Baja as a peninsula. Cortés’ hopes for the region as a source of gold and colonization were once again frustrated when Ulloa went missing under mysterious circumstances, leaving Cortés to return to Spain without thoroughly exploring the peninsula in 1541. While Juan Rodríguez Cabrillo attempted to explore the region in 1542 once again, this unfruitful venture was the last sponsored by the Spanish until Sebastián Vizcaíno’s unsuccessful expeditions fifty years later.

By that time, Spain had recognized that a supply station and intermediary colony would provide respite for ships traveling between Mexico and the Philippines on the increasingly busy trade routes. Although colonization attempts picked up in the late 17th century, a supply station was not firmly established until 1730 and two La Paz settlements were abandoned due to native resistance.

Spanish missions were the first to make a lasting foreign imprint on Baja soils. Juan María Salvatierra’s Misión Nuestra Señora de Loreto marked Spain’s first permanent residence that quickly developed into its religious and bureaucratic center. This colonization success spawned others, and 23 more missions were founded over the course of 70 years. However, the Jesuits were exiled from Baja at gunpoint in 1767 under the orders of King Carlos III of Spain who feared the Jesuits’ growing authority in the colonies.

Although the Jesuits’ forced retreat left a religious vacuum, it was quickly filled by the Franciscans and Dominicans. Father Junipero Serra led the way of the early Franciscans who either closed or merged the preexisting missions as well as established their own: San Fernando Velicatá. Serra led the Franciscan mission movement further north into modern day California, however, and left room for the Dominicans’ active presence on the peninsula in the 18th century. The Franciscans ultimately ceded control of Baja California Sur to the Dominicans in 1773.

The Dominican dominance evidenced Spain’s increased interest in the region as a transition area for trading ships as well as colonization interests. However, increased colonization correlated with increased violence and disease as was often the case. In result, the indigenous people of Baja underwent a significant decrease in their population.