Urriparacoxi, a powerful chief based in southern Lake County or eastern Orange County. For the next 280 years, the Spanish (and, between 1763 and 1783, the British) ruled Florida, but did not venture into the interior of the Florida peninsula south of the Oklawaha River valley (Acuera Province). The indigenous peoples of the Florida peninsula declined in numbers, and the people who became known as the Seminole moved into central Florida. United States control In 1821, Florida became a U.S. territory as a result of the Adams-Onis Treaty. In 1823 the Treaty of Moultrie Creek created a reservation in central Florida for the Seminoles and other Native Americans in Florida. What is now Polk County was within the boundaries of that reservation. An attempt to remove all Native Americans in Florida to west of the Mississippi River, starting in 1832, led to the Second Seminole War. Most of the fighting in the early years of the war occurred north of Polk County. By 1837, the Seminoles were being pushed south, and late that year Colonel Zachary Taylor, as part of a coordinated push against the Seminoles, led a column east from Fort Brooke (today's Tampa) into what is now Polk County, and then south between the Kissimmee and Peace river valleys, culminating in the Battle of Lake Okeechobee. By 1843 the few Seminoles remaining in Florida were confined to an informal reservation in southern Florida. While Florida gained statehood in 1845, it was not until 1861, a month after Florida had seceded from the Union, that Polk County was created. It was formed from the eastern part of Hillsborough County and named in honor of former US President James K. Polk, who had been popular with Southerners for supporting the expansion of slavery and whose 1845 inauguration was on the day after Florida became a state. Following the Civil War, the county commission established the county seat on donated in the central part of the county. Bartow, the county seat, was named after Francis S. Bartow, a Confederate colonel from Georgia who was the first Confederate brigade commander to die in battle. Colonel Bartow was buried in Savannah, Georgia with military honors, and promoted posthumously to the rank of Brigadier General. The original name of the town was Fort Blount. Several other towns and counties in the South changed their name to Bartow. The first courthouse built in Bartow was