The entry of Texas into the Union, boundary disputes with Texas, and the refusal to sell the California and New Mexican territories led to the

Mexico won independence from Spain in 1821. At that time, Mexico’s northern provinces included California, New Mexico, and Texas.

When Mexico founded the province of Texas in 1821, the land was very sparsely populated, so Texans actively recruited settlers from the United States to help grow the region’s population. Soon, Stephen Austin—after whom Austin, Texas is named—was selling plots of land to American settlers from a large land grant his father had received from the Mexican government; meanwhile, other settlers from the United States—especially from the American South—were moving to Mexican Texas.

By 1830, there were 7,000 settlers from the United States living in Mexican Texas. But tensions between the Mexican government and settlers from the United States grew as Mexico unsuccessfully attempted to halt further immigration and settlers pushed back against Mexican legal codes. These regulatory laws required those living in Mexico—including those living in Texas—to become Mexican, convert to Roman Catholicism, file legal documents in Spanish, and (after Mexico abolished slavery in 1829) end the practice of slavery. In reality, however, Mexico continued to allow settlers from the United States to bring slaves into the territory as “indentured servants.”

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