Age of Empires Series Wiki
Age of Empires Series Wiki

Intensive Aztec battle training gives your Heroes more hitpoints and attack.
—In-game description

Aztec Initiation is a technology in the vanilla Age of Empires III that can be researched at a Trading Post built on an Aztec settlement. Once researched, it increases the hit points and attack of hero units by 100%.

This technology was, to some degree, replaced by Sikh Gurus in The Asian Dynasties.