In 1868, the Muscogee (Creek) Nation confirmed its constitution and established Okmulgee, which means "bubbling waters," as its capital. After a grueling journey on the Trail of Tears, they settled in the Okmulgee area. Many brought their slaves, who would later join the tribe as freedmen after the Civil War and form the beginnings of a thriving African American community. As Okmulgee grew, white traders and settlers arrived in the burgeoning town. A post office was established, and in 1900 the Frisco Railroad line was built. By 1907, statehood loomed and oil fields dotted the landscape. This boom would continue until the Great Depression. World War II brought the construction of the Glennan Military Hospital, which cared for American service members and German prisoners of war from Oklahoma prison camps. Okmulgee's interesting cultural history continues to be preserved today.