Historia general de las cosas de nueva España (General history of the things of New Spain) is an encyclopedic work about the people and culture of central Mexico compiled by Fray Bernardino de Sahagún (1499–1590), a Franciscan missionary who arrived in Mexico in 1529, eight years after completion of the Spanish conquest by Hernan Cortés. Commonly referred to as the Florentine Codex, the manuscript consists of 12 books devoted to different topics. Book VII is about the sun, the moon, and the stars. It contains an account of the creation of the sun and the moon in what the Aztecs called the “fifth age of the world,” which Sahagún drew from ancient poems and legends shared with him by the elders. The illustration at folio 228v depicts the rabbit in the moon. The ancient Mesoamericans claimed that the outline of a rabbit could be seen in a full moon, a visual effect that results from the combination of dark spots caused by the alteration of rises and craters on the moon’s surface, but which they explained mythologically. In the Aztec account, before the creation of the day the gods met at Teotihuacán to create the sun so that it might illuminate the world. For this to happen, someone had to sacrifice himself. The god Tezcuciztecatl (also seen as Tecciztecatl) volunteered, but another god was also required. Everyone else was afraid and no one stepped forward, so they turned to Nanahuatzin, who was covered with pustules, and he accepted gracefully. Both gods prepared themselves for sacrifice by doing penance for four days. Tezcuciztecatl performed self-sacrifice using feathers, gold, and sharp fragments of precious stones and coral, while Nanahuatzin used humble materials and offered up his blood and pus. A large fire was lit and all the gods gathered around it at midnight, but when the moment came for Tezcuciztecatl to throw himself into the fire to be transformed into the sun, he hung back. Nanahuatzin, in contrast, bravely threw himself into the fire and began to shine. Only then did Tezcuciztecatl, who was envious, follow suit to be transformed into a second sun. The gods had not reckoned on there being two lights of equal brightness in the sky, so one of them took a rabbit and hurled it into the second sun to diminish its brightness, which is how it came to be the moon, with the shape of a rabbit visible on its face.