1. The original page 13 of the Codex Borbonicus, showing the 13th trecena of the Aztec sacred calendar

The original page 13 of the Codex Borbonicus, showing the 13th trecena of the Aztec sacred calendar

The original page 13 of the Codex Borbonicus, showing the 13th trecena of the Aztec sacred calendar