Since the 1500's when the Spanish claimed the territory, present-day Texas has been part of Spain, France, Mexico, the Confederacy, and the United States of America. It was also an independent republic.
Between 1824 and 1876, nations drafted founding documents which established the entity of Texas and defined the rights of its citizens and the powers of government.
The current Constitution of the State of Texas was originally approved in 1876 and is regularly amended.