Antonio López de Santa Anna, often referred to as Santa Anna, was the 8th President of Mexico and Mexican general during the Battle of the Alamo.
In the Timeless Universe
In the original timeline, on March 6, 1836, Santa Anna and his 4,000 troops kill 180 men in the Alamo in less than an hour, including notable figures Jim Bowie, Davy Crockett, and William B. Travis. The women and children of the Alamo were spared, and word of what happened at the Alamo spread throughout the United States. Travis' "Victory or Death" letter also escapes with the women and children. The letter is reprinted in many American newspapers and it motivates the United States to defeat Santa Anna's troops and annex Texas.
In the altered timeline, Garcia Flynn bribes Santa Anna with bars of gold he claims he got from Queen Isabella II. Santa Anna thinks Flynn is a spy sent by Isabella to meddle with him. Flynn denies that he will meddle with Santa Anna and confirms that he's there to help crush the rebellion.
Flynn later kills William B. Travis before he writes his "Victory or Death" letter to prevent it from giving the rebellion extra vigor. Santa Anna then raises the red flag, meaning that they will not spare the women or children. Flynn finds this objectionable, because the women and children are innocent. Santa Anna responds by saying that if they spare the women and children, the word of the Alamo will get out despite stopping the letter from being written. Flynn tries to make an emotional argument for sparing the women and children, because he knows what it's like to be a father and lose children. Santa Anna simply replies that war means that there will be sacrifices. Santa Anna in rage affirms that it's his war, not Flynn's, and he makes the decisions. He threatens to kill Flynn if he tries to interfere further.
Despite Santa Anna's attempt to kill the women and children of the Alamo along with the men, they still escape. They are able to escape because of Wyatt Logan's strategy to stall Santa Anna's forces long enough for Rufus Carlin to find a way out of the Alamo through the blocked aqueduct. Lucy Preston writes her own version of Travis' "Victory or Death" letter which escapes with the women and the children of the Alamo. The letter is delivered to General Sam Houston by John William Smith and it has a similar effect on the nation as Travis' letter. The United States is motivated by the letter and Santa Anna is defeated.
Antonio López de Santa Anna at Wikipedia