A photocopy of the original page 13 of the Codex Borbonicus, showing the 13th trecena of the Aztec sacred calendar (tonalpohualli). This 13th trecena was under the auspices of the goddess Tlazolteotl, who is portrayed wearing a flayed skin, giving birth to Cinteotl. The 13 day-signs of this trecena, starting with 1 Earthquake, 2 Flint/Knife, 3 Rain, 4 Flower, etc., are shown on the bottom row and, starting with 8 Lizard, 9 Snake, 10 Death, etc., in the column going up along the right side.