Early Chinese historians described Wo as a land of hundreds of scattered tribal communities rather than the unified land with a 700-year tradition as laid out in the 8th-century work "Nihon Shoki", a partly mythical, partly historical account of Japan which dates the foundation of the country at 660 BC. Archaeological evidence also suggests that frequent conflicts between settlements or statelets broke out in the period. Many excavated settlements were moated or built at the tops of hills. Headless human skeletons discovered in Yoshinogari site are regarded as typical examples of finds from the period. In the coastal area of the Inland Sea, stone arrowheads are often found among funerary objects.