The Republic of Texas () was a sovereign state in North America that existed from March 2, 1836, to February 19, 1846, that bordered Mexico, the Republic of the Rio Grande in 1840 (another breakaway republic from Mexico), and the United States of America, although Mexico considered it a rebellious province during its entire existence despite the Treaties of Velasco of May 1836. It was bordered by Mexico to the west and southwest, the Gulf of Mexico to the southeast, the two U.S. states of Louisiana and Arkansas to the east and northeast, and United States territories encompassing parts of the current U.S. states of Oklahoma, Kansas, Colorado, Wyoming, and New Mexico to the north and west. The Anglo residents of the area and of the republic became known as Texians. The region of the Mexican state of Coahuila y Tejas, now commonly referred to as Mexican Texas, declared its independence from Mexico during the Texas Revolution in 1835–1836, when the Centralist Republic of Mexico abolished autonomy from states of the Mexican federal republic. The major fighting in the Texas war of independence ended on April 21, 1836, but the Mexican Congress refused to recognize the independence of the Republic of Texas, as the agreement was signed by Mexican President General Antonio López de Santa Anna under duress as prisoner of the Texians, and the majority of the Mexican Congress did not approve the agreement. Intermittent conflicts between Mexico and Texas continued into the 1840s. The United States recognized the Republic of Texas in March 1837 but declined to annex the territory at that time. The Republic claimed borders based upon the Treaties of Velasco between the newly-created Texas Republic and General Santa Anna, who had been captured in battle. The eastern boundary had been defined by the Adams–Onís Treaty of 1819 between the United States and Spain, which recognized the Sabine River as the eastern boundary of Spanish Texas and western boundary of the Missouri Territory. Under the 1819 Adams–Onís Treaty, before Mexico's 1821 independence, the United States had renounced its claim to Spanish land to the east of the Rocky Mountains and to the north of the Rio Grande, which it claimed to have acquired as part of the Louisiana Purchase of 1803. The republic's southern and western boundary with Mexico was disputed throughout the republic's existence, since Mexico disputed the independence of Texas. Texas claimed the Rio