The Aztec legal system was highly complex and was designed to maintain social order and respect for government institutions. Aztec laws were based on royal decrees and on customs that had been passed down from generation to generation. These laws were also interpreted and applied by Aztec judges in the various court systems. Aztec judges were not necessarily bound by existing law, and had some discretion to do what was just and reasonable under the circumstances. The concept of stare decisis did apply in certain situations, as punishments ordered in certain cases were typically applied to subsequent similar cases.
The major civil and criminal laws were written down in pictograph for use by judges, while other customary laws were passed down to younger generations through spoken hymns. At the time of the conquest, the Aztecs had just begun to codify their laws into a more formal written form. However, the Spanish missionaries deliberately destroyed the few written court and legal records that existed because they were considered to be heretical. Other legal manuscripts were burned by Spanish troops for fuel, or were allowed to rot from humidity and neglect. As a result, the limited information that is available about the Aztec legal system comes from Spanish chroniclers and troops who documented their observations during the two years before Tenochtitlan was conquered.
Many Spanish priests also studied the Aztecs during the years immediately following the Conquest, and wrote manuscripts known as codices. These codices discussed Aztec history, religion, natural history, warfare, political affairs, and the events following the Conquest. The best and most comprehensive work was the 12 volume General History of the Things of New Spain, which was also known as the Florentine Codex. Written by Fray Bernardino de Sahagún, this work was based on interviews with Aztec elders who survived the Conquest, and includes detailed information about Aztec daily life, merchant and artisan business practices, and the governance of the Aztec empire. Because this codex provides a relatively pro-Aztec viewpoint of the Conquest, it was suppressed for 300 years during the Spanish inquisition. The Codex Mendoza, which was commissioned in the 1540s by a Spanish viceroy, is also an important resource because it covers the history of Tenochtitlan, has detailed tribute records, and includes a discussion of Aztec law and punishments. The Libro de Oro Codex (the Codex Ixtlilxóchitl) was written by Fray Fernando de Alva Cortés Ixtlilxóchitl and contains a collection of 65 criminal laws that were supposedly copied from an original Aztec manuscript.
Sources: Aguilar-Moreno (2006), Avalos (1994), Carter (1964), Kellogg (1995), and Smith (2003).
Image Information: Top image - Aztec judge conducting a court hearing (Sahagún, Historia de...Nueva España). Bottom image - Aztec judge sentencing an erring official (Sahagún, Historia de...Nueva España).