In these directions the religion of the nation tends to rise above that of the tribe. The tribal worships may continue almost as they were, the tribal gods may still be worshipped, the tribal jealousies and conflicts still be carried on in spite of the new union, and all the superstitions of early religion may long survive; yet a new religious force has appeared which will in time produce a complete new system. The true principle of classification, therefore, must be drawn from the difference between tribal and national religion, as this is the most vital difference, and that from which all the others which we mentioned may be derived. The transition thus sketched took place at widely different periods in different parts of the world; it began early and has taken place even in modern times, while very many tribes in various parts of the globe have not yet arrived at it. It is a transition of which it is manifestly impossible to exhibit the detail; in most cases the detail is not known, and it were a profitless task to trace how primitive religions met, united or remained apart, and how their crossings in one case led to a national religion, and in many others led to no such result. Much, no doubt, is to be found on such points in special works, and much still remains to be discovered. Various instances of the formation of national religions will meet us in our subsequent chapters. The Inca Religion.--We give, however, at this point an example of the transition we have described, drawn from a quarter remote from the great movements of history, and in which the facts are plain and uncontested. Of the two great civilised communities of the New World, discovered by the Spaniards in the sixteenth century, Mexico presents a worship compounded of many elements, which, along with high and lofty morality and great magnificence of ritual, yet retains an extraordinary amount of cruelty and savage horror. In Peru, however, we find a state religion which superseded savage cults still remembered in the country, and from the _Royal Commentaries of the Incas_, written by the Inca Garcilaso de la Vega in the beginning of the seventeenth century,[1] we are able to describe the religion of Peru both before and after the Inca reformation. [Footnote 1: Printed by the Hakluyt Society.]