Our knowledge about diseases in the prehistoric era of Japan is extremely limited because not much paleopathological research has been done thus far. For the little information we have about the occurrence of diseases during the early historic period we have to rely on a small number of literary sources. One general assumption, however, may be made from the geographic situation of the Japanese islands: Prior to more extensive contact with the Asian continent, Japan may have been free from regular epidemics of certain contagious diseases such as smallpox and plague. The most important sources on the early history of Japan are the Kojiki (The Ancient Chronicle), completed in A.D. 712, and the Nihonshoki (The Chronicles of Japan), completed in A.D. 720. Both these chronicles include references to diseases that af fected individuals, as well as to epidemics. The Kojiki informs us that there “raged many plagues” at the time of Emperor Sujin, who was supposed to be the first Emperor and to have reigned around the end of the third century A.D. The Nihonshoki confirms that “plagues spread out everywhere in Japan.” These epidemics may have been caused by climatic irregularities at that period; one passage in this source states: “Because the winter and the summer exchanged their places and the cold and heat occurred in irregular order, the plagues spread and the people suffered.” Considering the influence of these climatic changes on the crops, one may speculate that these epidemics were famine-related dysenteries. A passage in the Nihonshoki describes the symptoms of a princess at the court who had fallen ill, by stating that she “lost her hair and became very thin” - symptoms suggestive of high fever and dehydration that might accompany such forms of dysentery.