On March 1, 1845, John Tyler, the outgoing U.S. president, signed into law a joint resolution that authorized the admission of the Republic of Texas to the United States as a state. On December 29, 1845, the new president, James Polk, signed into law the act of Congress accepting the constitution of the State of Texas and bringing Texas into the Union. Polk’s signature completed a process begun nine years earlier, when Texas won its independence from Mexico at the battle of San Jacinto and offered itself to be annexed to the United States.