Begun in 1875, the Union Agency Building was the first building erected by the U.S. government to house the superintendencey of the Five Civilized Tribes. Used briefly for that purpose, it was leased in 1875 to the Baptist Mission Society as a school for Creek Freedman children. In 1891 the Creek Nation purchased the building from the U.S. and used it for a Creek Freedman orphanage. In 1909 the Creek Nation conveyed the property to the City of Muskogee for park purposes. At times different persons operated tearooms there, and Mrs. Alex Posey had a tearoom and small museum there from 1917 to 1919. Following World War I, in 1920 the building was renovated, renamed the Chateau, and used by the American Legion for offices and a dance hall. In 1944 the city returned the building to the government to aid the nearby veterans hospital. After standing unused, it was later returned to Muskogee through a bill sponsored by the Da-co-tah Indian Club of Muskogee and introduced in Congress by the Honorable Ed Edmondson. The Five Civilized Tribes Museum, incorporated in 1955 and located in the building since 1966, preserves the traditions and records of the Cherokee, Chickasaw, Choctaw, Creek, and Seminole peoples whose diverse trails in history converged in the Union Indian Agency.