Buddhism was introduced into Japan in the sixth century, but it had at first little influence on the native religion. Two centuries later a process of pacific penetration began which had some curious and important results. The missionaries of Buddhism applied to the Shinto gods a principle which had been already adopted in China. They discovered that whether Nature-gods or Man-gods they were nothing more than avatars or incarnations of the various Buddhas. The Sun-goddess, for example, was made out to be Vairochana, the Buddhist personification of essential _bodhi_ (enlightenment) and absolute purity; and deified men received the Buddhist titles of _Gongen_ (avatar) or _Bosatsu_ (saint). Iyeyasu, the founder of the Tokugawa dynasty of Shoguns, is the Gongen-sama _par excellence_. =Ryôbu Shinto=, which was in practice little more than a form of Buddhism, was the result of this process. Its principal founder was the famous Kōbō Daishi. At a later time other similar schools or sects were originated which drew their inspiration from Chinese philosophy or from Buddhism. Under these influences the true Shinto was much neglected. The Mikados themselves, after a few years of reign, shaved their heads and became Buddhist monks. One of them called himself a slave of Buddha. The greater Shinto ceremonies were omitted, or worse still, were performed by Buddhist monks, who also took possession of many of the Shinto shrines and celebrated Buddhist rites there. It should not be forgotten that the foreign religion contained valuable elements unknown to the older Shinto, and that the latter had much to gain by their absorption. The Ryōbu Shinto inculcated uprightness, purity of heart, charity to the poor, humanity, and the vanity of mere outward forms of worship; of all which there is little trace in the older cult.