Left: the bennu bird, aka phoenix, from a Ptolemaic papyrus (c.305-30 BC), the mythical bird thought to be the form of the new born sun, or that which carried the sun at its birth, each day. [1] Right: a depiction of the "benu bird" on the Papyrus of Ani version of the Egyptian Book of the Dead. [2]

“The phoenix, Egyptian bennu, which classic and Christian artists often represented as an eagle, was imagined by the Egyptians rather as a heron, and was depicted with two long feathers growing out at the back of its head, and sometimes also with a tuft hanging from its breast. The name bennu signifies ‘that which revolves’ or ‘turns back’.

Myths told how the bird was born from the midst of flames which arose from out of the summit of a tree in Heliopolis, and that it was known to men by the beauty of its song, to which even the sun himself love to listen. The phoenix symbolized the morning sun arising out of that fiery glow of dawn which dies away as the new born luminary ascends the sky, and hence was regarded as the bird of Ra. But since the dead sun was held to become an Osiris and the new Sun to arise from the embalmed body of the old which had been duly brought to Heliopolis, in like manner also the phoenix was supposed to be a form of Osiris in which the god returned to his own country.

Further, as on the death of the sun it was from the Osiris sun that the phoenix sun arose, so it was taught in the case of humanity also that it was from his ‘own Osiris’ that there sprang the new man of the resurrection, and of this resurrection the phoenix became a symbol from a very early date. Hence, even in funerary texts of the Old Kingdom [c.2500BC] the deceased was likened to the phoenix: later it continued to serve as a symbol of the resurrection, and as such it is mentioned in patristic literature and figures in earliest Christian art.”

“The next representation [chapter 17; plate 7 (page 46)] [image segment #6] is of a heron standing before an offering-stand with a flower on top. The accompanying caption identifies this bird as benu ‘the heron’, a Heliopolitan deity associated with the beginnings of creation as a manifestation of Atum, or Re [Ra] as creator deity. The benu is often described as the ‘Egyptian phoenix’, an error which may derive from Herodotus, who has transmitted a faulty description of a legend he claimed to have heard from priests of Heliopolis. In the Egyptian legends, however, the benu is not reborn from his ashes after a fiery death; rather, the benu made his appearance on the primordial mound when the land emerged from the water, bringing the light with him, a concept fundamental to Heliopolitan religion. As an example of how puzzling the glosses in the accompanying text can be, the benu is said to be Osiris in one explanation and Osiris’ corpse in the other, two associations the benu does not seem to have outside this chapter.”

— Ogden Goelet (1994), “Commentary on the Corpus of Literature and Tradition Which Constitutes the Egyptian Book of the Dead, the Book of Going Forth by Day” (image, pg. 46; text, pg. 169) [2]