[2][3] Tizoc was a son of the princess Atotoztli II and her cousin, prince Tezozomoc.
He was an uncle of Emperors Cuauhtémoc, Moctezuma II and Cuitláhuac and grandfather of Diego de San Francisco Tehuetzquititzin.
Most sources agree that Tizoc took power in 1481 (the Aztec year "2 House"), succeeding his older brother.
Although Tizoc's reign was relatively short, he began the rebuilding of the Great Pyramid of Tenochtitlan (a task completed by his younger brother in 1487), and also put down a rebellion of the Matlatzincan peoples of the Toluca Valley.
According to the Codex Mendoza, during Tizoc's reign the āltepēmeh of Tonalimoquetzayan, Toxico, Ecatepec, Cillán, Tecaxic, Tolocan, Yancuitlan, Tlappan, Atezcahuacan, Mazatlán, Xochiyetla, Tamapachco, Ecatliquapechco and Miquetlan were conquered.