Where they came from can only be guessed at, and what they left behind has already been well documented, but rarely as in Davies' broad narrative history has the pre-Hispanic sensibility been so absorbingly dramatized or made sense of The Aztecs, or Mexica, although originally a nomadic tribe, built an astonishingly vast domain through conquests that -- unlike the European pattern of empire -- followed trade, a loosely-knit federation relying on allies and associates (its great weakness) rather than, as with Old World cultures, a system of direct or proconsular government. Nevertheless, among their warrior-rulers Moctezuma I would stand comparison with Julius Caesar and Ahuitzall with Alexander the Great. What has always intrigued historians, of course, is the Aztecs' highly formalized ritual of human sacrifice (and self-sacrifice) on a scale so immense that it's impossible for us to comprehend. But what interests Davies even more is the victims, why they went so willingly -- as if through some mystical transformation the sacrificed became gods and in a sense died as gods and not for the gods. Equally curious -- there seems to have been no hatred or cruelty intended by the slaughters, a concept unbelievable to the conquistadores who themselves killed for retribution as well as gold. Even after the Spaniards introduced Christianity, sacrifices continued for a time, and indeed the friars hit on a ritual of their own -- throwing live animals into an open fire, they discovered, was an effective way to teach the fear of God.