Built in 1780 by George Rogers Clark as part of an impressive settlement plan conceived by Gov. Patrick Henry of Virginia and later pursued by and named for Gov. Thomas Jefferson, Fort Jefferson was intended to protect the US claim to its western border and serve as a key trading post. In 1781, the Chickasaws, led by a Scotchman, Colbert, and aroused by use of their land without consent, besieged the fort for 5 days, killing many settlers. Those who remained became desperate for provisions, which were already low because of the difficulty of reaching the fort, until Gen. Clark arrived with reinforcements and supplies and the Indians withdrew. The fort was abandoned thereafter, later resettled after Jackson Purchase, and became an important Union post in the Civil War.