His existence is known from two sources: one is a mummy-label found on the mummy of his daughter Nebetia, where he is mentioned as her father; the other is a Saqqaran relief of his tutor, Meryre, where a person named Siatum is depicted sitting on Meryre's knee. There is no direct evidence linking the two persons – Nebetia's father and Meryre's pupil – together, but the style of the relief dates it to Amenhotep's reign, so Meryre must have been tutor either during Amenhotep's or his predecessor's reign, and Siatum's name corresponds to part of Thutmose's Horus name.
