Age of Empires Series Wiki

Formal European recognition of the Mapuche nation provides approximately 100 Coin in crates for every 2 minutes of game length, up to 30 minutes.
—In-game description

Mapuche Treaty of Quillin is a technology in Age of Empires III: The WarChiefs that can be researched at a Trading Post built on a Mapuche settlement once the Fortress Age is reached. Once researched, it ships 100 coin for every 2 minutes the game have passed, up to 30 minutes (for a total of 1,500 coin).

This technology acts as a replacement to Aztec Chocolate Recipes in the vanilla Age of Empires III.