The Texan Revolution began in October 1835 when the largely-American immigrants in the Mexican province of Texas rebelled against the Mexican government. Official immigration had begun a decade earlier, and a number of the immigrants had pressed for the province to secede and join the United States. Although they had gained control of Texas by December and attracted hundreds of volunteers from the United States, the rebels did not formally declare independence until the following March. However, the dictator Santa Anna had already arrived in February, and his army quickly won several victories. Since Santa Anna had ordered all rebels to be executed, the Texians (English-speaking Texans) retreated until Sam Houston captured Anna at the battle of San Jacinto.