The Change in California: From Spanish to Mexican Control
In 1821, California went from being part of Spain to being part of Mexico. This change brought new laws and a shift of power from Spanish missionaries to Mexican governors and powerful families who owned ranches. These changes affected the way people lived, worked, and even how the land was used. Mexican settlers, Russian colonists, American fur trappers, homesteaders, and European traders all arrived in California, bringing new people and ideas.

The Decline of the Mission System
In the early 1800s, the Spanish built missions in California. These missions served as churches, schools, farms, and places for Native Americans to live. However, after Mexico gained its independence from Spain in 1821, the new government wanted to take control of the mission land. In 1834, the Mexican government took most of the mission lands and gave them to local landowners. This was called "secularization." This meant that the Native Americans who had worked on the missions lost their homes and land.

The Rise of Ranching and the Californios
After the missions were closed, the ranching industry grew. The Mexican government gave large pieces of land to families who helped them. These families were called "Californios." They raised cattle and traded hides and tallow (fat) with American ships. Californios became rich and powerful, but most Native Americans were forced to work for them on the ranches. Many Native Americans were treated badly and worked in poor conditions.

New People in California
During the 1830s and 1840s, more Europeans and Americans came to California. Some of them became Mexican citizens, converted to Catholicism, and married into Californio families. Many Americans believed California was a land of plenty and saw the Californios as lazy. They wanted California to be part of the United States. This idea was called "Manifest Destiny," the belief that the U.S. should spread across the continent.

The U.S.-Mexican War and California’s Change
In 1846, the U.S. and Mexico went to war. The war lasted less than a year, and by the end, the U.S. controlled California. The land that was once part of Mexico was now part of the United States, and California’s changes were just beginning.

Source: Essay: 1821-1847: Missions, Ranchos, and the Mexican War for Independence
Calisphere.org at The University of California