In 1830, President Andrew Jackson authorized the removal of eastern Native American tribes to west of the Mississippi River. The U.S. government and some Seminole chiefs discussed the removal, though details of an agreement are still unclear. In 1835, U.S. troops began enforcing the emigration. Many Seminoles resisted leaving their homes, leading to violence. Chief Micanopy led warriors to ambush U.S. troops along a military route, and resistance leader Osceola killed a prominent government agent. The Battle of Okeechobee became one of the bloodiest battles of the Second Seminole War. After a lengthy pursuit of 150 miles, Colonel Zachary Taylor's brigade of 803 U.S. troops came upon 380 Seminole warriors positioned for battle in a cypress hammock along the lake shore. The Seminoles had strategically positioned themselves to gain an advantage, forcing Taylor's troops to struggle through nearly a mile of muck and sawgrass before coming under fire. Although the Seminoles ultimately retreated as part of their guerrilla war tactics, the battle was an overwhelming victory for them. The war dragged on for seven years and cost thousands of lives, and by the end only 300 Seminoles remained in Florida. Colonel Richard Gentry, who commanded the regiment of Missouri Mounted Volunteers with Taylor's force, was mortally wounded early in the battle and died later that night. Coacoochee, nephew of Micanopy, led a band of Seminole warriors at Okeechobee alongside those of Abiaka and Alligator after escaping wrongful capture under a flag of truce. Abiaka, a respected medicine man and battle leader, never surrendered to the U.S. Army and later led the remaining Seminoles in the state to Big Cypress Swamp, where they continue to thrive today.