As before stated, there were many tribes, consequently many languages, although some of them were near enough alike that members of different tribes could be readily understood. Also the characteristic traits varied in different tribes. It is not known whence they came, although their tradition points to the origin of the northwest. Undoubtedly, each tribe had a myth of its own origin, but, generally speaking, they all came from the northwest. Without doubt, at the time of the coming of the Spaniards, the tribes were non-progressive except in {192} government. The coming of the Spaniards was a rude shock to their civilization, and with a disintegration of the empire, the spirit of thrift and endeavor was quenched. They became, as it were, slaves to a people with so-called higher civilization, who at least had the tools with which to conquer if they had not higher qualities of human character than those of the conquered. _The Earliest Centres of Civilization in Mexico_.--Prior to the formation of the empire of the Aztecs, conquered by the Spaniards, there existed in Mexico centres of development of much greater antiquity. The more important among these were Yucatan and Mitla. A large number of the ruins of these ancient villages have been discovered and recorded. The groups of people who developed these contemporary civilizations were generally known as Toltecs. The Maya race, the important branch of the Toltecs, which had its highest development in Yucatan, was supposed to have come from a territory northeast of Mexico City, and traces of its migrations are discovered leading south and east into Yucatan. It is not known at what period these developments began, but probably their beginnings might have been traced back to 15,000 years, although the oldest known tablet found gives a record of 202 years B.C. Other information places their coming much later, at about 387 A.D.