sentences:  Sahagún's date precedes the Durán's observations by several decades and is believed to be more recent to the Aztec surrender to the Spanish.Both are shown to emphasize the fact that the beginning of the Native new year became non-uniform as a result of an absence of the unifying force of Tenochtitlan after the Mexica defeat.The 20-day months () of the Aztec solar calendar were called (in two sequences)