The nature of the opposition which the ancient religion of Japan could offer to the introduction of any hostile alien creed, should now be obvious. The family being founded upon ancestor-worship, the commune being regulated by ancestor-worship, the clan-group or tribe being governed by ancestor-worship, and the Supreme Ruler being at once the high-priest and deity of an ancestral cult which united all the other cults in one common tradition, it must be evident that the promulgation of any religion essentially opposed to Shinto would have signified nothing less than an attack upon the whole system of society. Considering these circumstances, it may well seem strange that Buddhism should have succeeded, after some preliminary struggles (which included one bloody battle), in getting itself accepted as a second national faith. But although the original Buddhist doctrine was essentially in disaccord with Shinto beliefs, Buddhism had learned in India, in China, in Korea, and in divers adjacent countries, how to meet the spiritual needs of peoples maintaining a persistent ancestor-worship. [184] Intolerance of ancestor-worship would have long, ago resulted in the extinction of Buddhism; for its vast conquests have all been made among ancestor-worshipping races. Neither in India nor in China nor in Korea,--neither in Siam nor Burmah nor Annam,--did it attempt to extinguish ancestor-worship, Everywhere it made itself accepted as an ally, nowhere as an enemy, of social custom. In Japan it adopted the same policy which had secured its progress on the continent; and in order to form any clear conception of Japanese religious conditions, this fact must be kept in mind.