Tensions had been high for years between the Americans who had come to settle Texas and the Mexican authorities.

When Mexico encouraged Americans to settle Texas, the immigrants were given land that Mexicans had not claimed. These Americans became Mexican citizens and were supposed to learn Spanish and convert to Catholicism. They never really became "Mexican," however. They kept their language and culturally had more in common with the people of the U.S. than with Mexico.

Most of the American settlers in Mexico were from Southern states, where slavery was still legal. They even brought their slaves with them. By the 1830s, many settlers were afraid that the Mexicans would take their slaves away, so slave owners wanted independence from Mexico.

The Constitution of 1824 allowed the Texans freedom to rule themselves. Santa Anna replaced this constitution with another that gave the federal government more control, and many Texans were outraged.

Texans found it hard to resolve their differences with the central Mexican government, as new governments often reversed decisions made by previous ones.

Texas was separated from most of Mexico by large stretches of desert with few roads. Selling their goods in Mexican ports was almost impossible. For Texan farmers, it was easier to send goods downstream to the coast, ship them to a nearby U.S. city, and sell them there. So the Texans had strong economic ties with the United States.

Texas was half of the state of Coahuila y Texas. From the beginning, the American settlers (and many of the Mexican Tejanos as well) wanted full Mexican statehood for Texas, as the state capital was far away and difficult to reach.

The Americans outnumbered the Tejanos by as many as four to one.

Many Americans believed that Texas, as well as other parts of Mexico, should belong to the United States. Political leaders such as Andrew Jackson secretly encouraged Texas settlers to rebel.

Stephen F. Austin was one of many Americans who immigrated to Texas planning on being good citizens of Mexico. After years of arguments with the Mexican bureaucracy, he changed sides and supported independence. He spent a year in a Mexican prison for supporting Texas statehood.

In 1835, the first shots of the Texas Revolution were fired in the town of Gonzales. After the Texans captured San Antonio, General Santa Anna marched north with a giant army. They overran the defenders at the Battle of the Alamo in 1836, the same year Texas formally declared independence.

Although Mexico tried several times in the next few years to reclaim Texas, the Republic of Texas joined the United States in 1845.

Source: Causes of Texas Independence
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