This game was published in Vae Victis magazine #139. It's a bonus for Cortés et la conquête du Mexique 1519-1521 which was published in Vae Victis #137 and offer to play these battles separately or with the campaign. It allows you to resolve the siege on a special tactical map when it is held in ZS 22 of Tenochtitlan or to independently simulate the Noche Triste (June 26 to July 1, 1520) and the siege of Tenochtitlan (May 26 to August 13, 1521).