Those Aztec warriors who demonstrated the most bravery and who fought well became either jaguar or eagle warriors. Of all of the Aztec warriors, they were the most feared. Both the jaguar and eagle Aztec warriors wore distinguishing helmets and uniforms. The jaguars were identifiable by the jaguar skins they wore over their entire body, with only their faces showing from within the jaguar head. The eagle Aztec warriors, on the other hand, wore feathered helmets including an open beak. The Florentine Codex is the common name given to a 16th century ethnographic research project in Mesoamerica by Franciscan friar Bernardino de Sahag?n. Bernardino originally titled it: La Historia General de las Cosas de Nueva Espana (The General History of the Things of New Spain). Bernardino conducted research, organized evidence, wrote and edited his findings starting in 1545 up until his death in 1590. It consists of 2400 pages organized into twelve books with over 2000 illustrations drawn by native Aztec artists.