Stuart noted that the Marcador monument at the Petén Basin center of Tikal records Spearthrower Owl's ascension to the throne of an unspecified polity on a date equivalent to 4 May 374 CE. Monuments at El Peru, Tikal and/or Uaxactun describe the arrival of a personage Siyaj K'ak' somehow under the auspices of Spearthrower Owl in the month of January 378. The exact date of his arrival in Tikal is identical with the death of the Tikal ruler, Chak Tok Ich'aak I. Tikal Stela 31 describes that in 379, a year after the arrival of Siyaj K'ak' at Tikal, Yax Nuun Ayiin, described as a son of Spearthrower Owl and not of the previous ruler Chak Tok Ich'aak, was installed as king of Tikal. His rule saw the introduction of Teotihuacan-style imagery in the iconography of Tikal. Stela 31 was erected during the reign of Yax Nuun Ayiin's son Siyaj Chan K'awil and describes the death of that ruler's grandfather, Spearthrower Owl, in 439 CE (Maya date 9.0.3.9.18).