alamo , ( spanish: ?cottonwood?) 18th-century franciscan mission in san antonio , texas , u.s., that was the site of a historic resistance effort by a small group of determined fighters for texan independence (1836) from mexico .the building was originally the chapel of the mission san antonio de valero , which had been founded between 1716 and 1718 by franciscans . before the end of the century, the mission had been abandoned and the buildings fell into partial ruin. after 1801 the chapel was occupied sporadically by spanish troops. apparently, it was during that period that the old chapel became popularly known as ?the alamo? because of the grove of cottonwood trees in which it stood.in december 1835, at the opening of the texas revolution (war of texas independence), a detachment of texan volunteers, many of whom were recent arrivals from the united states , drove a mexican force from san antonio and occupied the alamo. some texan leaders?including sam houston , who had been named commanding general of the texas army the month before?counseled the abandonment of san antonio as impossible to defend with the small body of troops available, but the rugged bunch of volunteers at the alamo refused to retire from their exposed position. on february 23, 1836, a mexican army, variously estimated at 1,800 to 6,000 men and commanded by general antonio lópez de santa anna , arrived from south of the rio grande and immediately began a siege of the alamo . estimates of the size of the small defending force (including some later arrivals) usually vary between 183 and 189 men, though some historians believe that figure may have been larger. that force was commanded by colonels james bowie and william b. travis and included the renowned frontiersman davy crockett . at the beginning of the siege, travis dispatched ?to the people of texas & all americans in the world? an impassioned letter requesting support. for 13 days the alamo's defenders held out, but on the morning of march 6 the mexicans stormed through a breach in the outer wall of the courtyard and overwhelmed the texan forces. santa anna had ordered that no prisoners be taken, and virtually all the defenders were slain (only about 15 persons, mostly women and children, were spared). the mexicans suffered heavy casualties as well; credible reports suggest between 600 and 1,600 were killed and perhaps 300 were wounded.
