The Tovar Codex, attributed to the 16th-century Mexican Jesuit Juan de Tovar, contains detailed information about the rites and ceremonies of the Aztecs (also known as Mexica). The codex is illustrated with 51 full-page paintings in watercolor. Strongly influenced by pre-contact pictographic manuscripts, the paintings are of exceptional artistic quality. The manuscript is divided into three sections. The first section is a history of the travels of the Aztecs prior to the arrival of the Spanish. The second section is an illustrated history of the Aztecs. The third section contains the Tovar calendar, which records a continuous Aztec calendar with months, weeks, days, dominical letters, and church festivals of a Christian 365-day year. In this illustration, from the second section, Coatepec, the Toltec city in Tula, is represented by a hill with a serpent or snake on it. Water leaping with fish flows from the hill. On the right is Tenoch (known from his glyph of a flowering cactus), the legendary hero who founded Tenochtitlan. On the left is Tochtzin (known from his glyph of a rabbit) from Calpan (known from the glyph of a house with a flag). The two rulers sit on basketwork thrones. The Toltec civilization was already in decline by the 12th century and was routed in mid-century by the Aztecs, who had left Aztlán and migrated to Tula. At Coatepec, meaning “hill of the serpent,” the Aztecs perfected certain technological skills and, at the suggestion of their god, Huitzilopochtli (the god of the sun and war), created the lake shown here.