At some point during its journey across the kingdom of Egypt, between 525 and 522 BCE, the army was waylaid by a sandstorm and lost to the desert. The army's existence shortly passed into story, and by 49 BCE was a legend known through Egypt.
Sometime around 38 BCE the Hidden One, Bayek of Siwa, travelled to the Seth-Anat Tomb in the Desheret Desert – built within the remains of the Isu construct Qeneb.too Kah'Aiye – in order to investigate rumours of a curse spreading up from Thebes. Whilst travelling to the tomb, the Hidden One was attacked by the ghostly apparitions of undead soldiers who supposedly were a part of the Lost Army of Cambyses. Upon returning the source of the curse to its rightful place within the tomb, the undead soldiers returned to the sands.