Tlaloc was an important deity in Aztec religion, a god of rain, fertility, and water. He was a beneficent god who gave life and sustenance, but he was also feared for his ability to send hail, thunder and lightning, and for being the lord of the powerful element of water. Tlaloc oversaw the crop growth, especially maize, and the regular cycle of the seasons. To appease this god, the Aztec people would offer up human sacrifices; in Tlaloc's case it was usually children. The Codex Borgia is a Mesoamerican ritual and divinatory manuscript. It is generally believed to have been written before the Spanish conquest of Mexico, somewhere within what is now today southern or western Puebla. The Codex Borgia is a member of, and gives its name to, the Borgia Group of manuscripts. Cardinal Stefano Borgia owned it before it was acquired by the Vatican Library.