Since Time Immemorial: Tribal Sovereignty in Washington StateOSPI - Office of Superintendent of Public Instruction, The Indian Education Office, private and public agencies, and several of the 29 Federally Recognized Tribes in Washington State have partnered and funded this ground-breaking curriculum initiative. All 29 tribes have endorsed its importance and use. This site houses resources, materials, lessons, and entire units to support the teaching of tribal sovereignty, tribal history, and current tribal issues within the context of OSPI recommended units for Washington and US history in the elementary and middle school levels and US history and Contemporary World Issues in the high school level.