Music and history are tightly interwoven in Native American life. A tribe's history is constantly told and retold through music, which keeps alive an oral narrative of history. These historical narratives vary widely from tribe to tribe and are an integral part of tribal identity. However, their historical authenticity cannot be verified; aside from supposition and some archaeological evidence, the earliest documentation of Native American music came with the arrival of European explorers. Musical instruments and pictographs depicting music and dance have been dated as far back as the 7th century. However, archaeological evidence shows that musical instruments in North America date to at least the Archaic period (ca. 8000–1000 BC), which includes instruments such as turtle shell rattles.