Minor Tepanec town on the western shore of Lake Texcoco, elevated in 1428 to the third, junior seat of the Aztec Triple Alliance (receiving a fifth of joint tribute) after the fall of its former overlord, Azcapotzalco.
Fell with Tenochtitlan and Texcoco to Cortés in 1521; the site is now the Tacuba neighborhood of Mexico City.
Already used for the canonical 'aztec' and 'azcapotzalco_tepanec' records; documents Tlacopan's specific one-fifth tribute share and junior role in the Triple Alliance's administrative structure.