John William Smith was the first mayor of San Antonio.
In the Timeless Universe
Wyatt Logan saves Smith from a pile of debris that landed on top of him. While Smith's wounds are being treated, Wyatt compliments Smith's toughness at such a young age. Smith reveals that his father and brothers were killed by Santa Anna.
Later, when the women and children of the Alamo were fleeing through the aqueduct, Lucy Preston finds out who Smith is. Lucy commands Wyatt to make Smith deliver her version of the William B. Travis' letter to General Sam Houston. She notes that he is also important to the timeline, as he grows up to be the first mayor of San Antonio. While Smith initially doesn't want to leave the Alamo because he feels the people there are the only family he has left, Wyatt is able to convince him to leave and deliver the letter to General Houston.
John William Smith at Wikipedia