Anglo migration into Spanish Texas began when Moses Austin received a Spanish land grant to establish a colony there, and after his death Stephen F. Austin carried on the effort, bringing his original 300 colonists into central Texas in 1823. By 1830 the Mexican government had become concerned about the growing number of Anglos entering Texas, and after Mexico won independence from Spain in 1821, the autocratic rule of President General Antonio López de Santa Anna Pérez de Lebrón and a newly instituted anti-federalist constitution deepened hostility between the Mexican government and settlers. Both Anglos and Tejanos rebelled against centralized authority from Mexico City and the harsh measures of the Santa Anna regime. Late in 1835, the Mexican state of Coahuila y Tejas rose in rebellion with the Battle of Gonzales, and on March 2, 1836, at the convention at Washington on the Brazos, independence from Mexico was declared. Santa Anna marched north to restore control, his forces killing the defenders at the Battle of the Alamo from February 23 to March 6, 1836, and executing 342 captured Texians at the Goliad Massacre on March 27, 1836. On April 21, 1836, Sam Houston's soldiers defeated Santa Anna at the Battle of San Jacinto while shouting "Remember Goliad, Remember the Alamo!" and a small band of Texian forces captured him the next day. Acting Texas president David G. Burnet and Santa Anna then signed the Treaties of Velasco, in which the full independence of the Republic of Texas was to be acknowledged in exchange for guaranteeing Santa Anna's life and transport to Veracruz, but a new government in Mexico City declared that Santa Anna was no longer president and the treaty was null and void. Even so, the war ended with the creation of the Republic of Texas. Texas sought annexation to the United States in 1836, but President Andrew Jackson refused because he feared war with Mexico; by popular vote Texas was annexed in 1845 as the 28th state. As feared, annexation led to the Mexican-American War, which ended in 1848 with the Treaty of Hidalgo after the U.S. Army defeated Santa Anna, adding 1,193,061 square miles to U.S. territory and eventually contributing to the western expansion of the United States.