These books constitute that part of the sacred literature of the Buddhists which contains the regulations for the outward life of the members of the Buddhist Samgha--nearly the oldest, and probably the most influential, of all Fraternities of monks. It is impossible to frame any narrower definition of the Vinaya than this, since the gradual change of circumstances in the Fraternity resulted in a gradual change also in the Vinaya itself. To give any more detailed account of what the Vinaya is, it will be necessary to trace what can be at present ascertained of its history; to show that is, so far as it is yet possible to do so--the causes which led to the establishment of the oldest Rules and Ceremonies of the Order, and to follow step by step the accretions of new literary work around this older nucleus.