On April 20 -- 21 , rebel forces under Texas General Sam Houston defeated the Mexican army at the Battle of San Jacinto .
Texans responded by declaring their independence from Mexico on March 2 , 1836 .
On April 20 -- 21 , rebel forces under Texans General Sam Houston defeated the Mexico army at the Battle of San Jacinto .
Texans responded by declaring their independence from Mexico on March 2 , 1836 .