Human sacrifice was common in many parts of Mesoamerica, so it is unfortunate for the Aztecs that they are largely lumbered with its odious reputation. Yet it didn’t seem odious to Aztec priests. As they explained to the Franciscan missionaries who put an end to the practice, in ripping out a beating human heart they were liberating a fragment of the Sun so that it could rejoin the orb on a trail of blood.