Japanese civilization still exists today. During the Yayoi Period, between III BC and III AD a patriarchal, agricultural society existed. Beginnings of the empire date back to Kofun period (III - VII AD) In 552 AD Buddhism was introduced in Japan. In 702 AD Taiho code was enforced, Japan being a country based on law. Between 710-794, during the Nara Period there was a culmination of Chinese influence. In the Heian Period that lasted from 794 until 1192 original court culture developed. In 1274 and 1281 there were two unsucessful Mongolian incursions, which were the only outer threat for Japan before modern times. In 1543 Portugese seammen came to ports in Japan.