I presume you know about the Battle of the Alamo. You'd better (at least my American readers had better). 1836, Davy Crockett, James Bowie, the Mexicans slaughtered the Texans, the later Battle of San Jacinto saw the Texans get revenge with the 'Remember the Alamo' battle cry. Symbol of San Antonio, Ozzy Osbourne peed on it once.
The question I'd like to ask you today is simple: why did the battle take place?
Well, the obvious answer is that it was part of Texas' attempt to declare independence from Mexico. But why did they declare independence is the main question here. The region was not only becoming increasingly disillusioned with changes in Mexican policy brought about by Mexican president Anastasio Bustamante and later successor Antonio Lopez de Santa Anna, but on top of that, Texas was increasingly being settled by American immigrants who were making up a larger and larger proportion of the population and eventually took control of the conversation.
Remember Texan sensibilities in the 1830's. Or more to the point, remember Texan sensibilities in the 1840's.
Santa Anna was a dictator and chased repeatedly into the hills over the years by angry Mexicans. Texas wasn't the only place in Mexico to see an anti-Santa Anna uprising. But they were the only one to declare independence. The straw that broke the camel's back was Santa Anna abolishing the Mexican Constitution of 1824 in 1835. However, not everyone was in favor of the constitution in the first place. Texans were fighting for all sorts of issues. There wasn't really any one major factor. Independence, hatred of Santa Anna, various personal factors, there were plenty of reasons Texas had and plenty of reasons the fighters at the Alamo had.
But it can be established that one of those reasons was slavery.
The Constitution of 1824, among other things, abolished slavery in Mexico. That statute took effect five years later in 1829, though Texas was allowed one extra year. It's plain to see what side of the issue Texas took, as when they were participating in the Civil War, they fought for the Confederacy and didn't actually enter the Union until after the close of the war. Those American immigrants had mostly come from the south. A quarter of Texas was slave-owning, and they wanted slavery back.
After the Alamo, pretty much every pre-existing reason got wiped from the record and the Alamo itself became the reason. As a play to convince the slave population to support Mexico over Texas, Santa Anna spared the slave of one of the Alamo fighters, a slave named Joe, who also fought. (A number of noncombatant women and children were also spared to spread the word of the Texan defeat.) Joe, upon his return to Texas, was questioned about the events at the Alamo, and after giving his account, he was then sent back to his master's farm while Texas reared up to take revenge at San Jacinto.
How Joe truly felt about the whole affair appears largely beside the point, but we know that on the first anniversary of the Battle of San Jacinto, Joe made a break for it. Texas remembered the Alamo so well that a $40 reward was offered for the return of the runaway slave.
They never caught him.