Before 1836, Texas had been ruled by a number of nations. Originally, Spanish colonists had conquered Mexico and then established colonies in Texas. Back then, Texas was a part of Mexico and both were ruled by Spain.
But then in 1821, Mexico gained independence from Spain. So Texas became a part of Mexico and Mexican government started exerting control over it. When the Texas Revolution began in 1835, Mexican government was the one ruling over Texas.
In 1835, disagreements arose between the Mexican government and the white settlers in Texas. By this time, a huge number of white settlers from American states had arrived and settled in Texas. Mexican authorities under General Santa Anna announced that all local militias should be disbanded.
When Mexican government tried to impose this over the American settlers, they rebelled. They thought that Mexican government wanted to disband militia so that the Mexican army could then take over Texas.
The Texan Revolution began in 1835 and continued until late 1836. It concluded with the victory of the Texans and the complete retreat of the Mexican army from Texas. Once the revolution was successful, the Republic of Texas was born.
This was one of the most famous events of the Texas Revolution. A group of Texan soldiers defended the fort of Alamo against a large Mexican army. The Texans numbered at only 200 while the Mexican army numbered around 2000 soldiers.
The Texans held off the Mexican army for 13 days but then the fort was stormed by Mexican soldiers in March, 1836. Mexican army killed every Texan soldier. This later inspired many new Texans and volunteers to join the Texan army and fight the Mexicans.
After securing victory in the Battle of the Alamo, the Mexican army under General Santa Anna continued to advance. Santa Anna wanted to defeat the remaining Texan army and end the rebellion. But when he reached San Jacinto, his army was confronted by a large Texan army.
At this point, Texans were very angry because the Mexican army had killed a large number of their soldiers, even those who had surrendered.
So when the battle began on April 21, 1836, the Mexican army was defeated within minutes and hundreds of Mexican soldiers were killed. With this battle, the Mexican army’s morale was weakened and it eventually retreated out of Texas.
The defeat of General Santa Anna’s army at San Jacinto and the capture of general effectively ended major fighting in the Texas Revolution. The rest of the Mexican army slowly moved back towards the border and eventually left Texas to head back to Mexico.
Texans elected a legislature of their own and declared themselves to be citizens of the Republic of Texas. Although Mexico agreed not to continue fighting Texas, Mexico refused to accept the independence of Texas.
When later in 1845, Texas became the 28th state of United States of America, Mexico attacked Texas once again and a new war began.