The Treaty of Bird's Fort between the Republic of Texas and several Native American tribes was signed in 1843 at Bird's Fort in present-day Arlington, Texas. Article XI of the treaty provided that no one may "pass the line of trading houses" (at the border of the Indians' territory) without permission of the President of Texas, and may not reside or remain in the Indians' territory. These "trading houses" were later established at the junction of the Clear Fork and West Fork of the Trinity River in present-day Fort Worth. At this river junction, the U.S. War Department established Fort Worth in 1849 as the northernmost of a system of 10 forts for protecting the American Frontier following the end of the Mexican–American War. The city of Fort Worth continues to be known as "where the West begins".