Aztec burial ritual, 16th century. Illustration of the shrouded body of an Aztec emperor (centre) seated on a basketwork throne during burial rituals. At right is a quetzal-plumed epaulette. At lower right is a jade collar. Three men (upper right) represent the slaves sacrificed when an emperor died. The Aztec Empire (ruled by the Mexica) was an alliance of three city states that ruled in the highlands plateau area of central Mexico from 1428 until their defeat by Spanish conquistadors in 1521. Artwork from a 19th-century copy of a 16th-century post-conquest codex and history of the Aztecs by Jesuit missionary Juan de Tovar.