From Eberhard Otto, Egytpian Art and the Cults of Osiris and Amun

A recumbent Osiris is made active, and potent, by his sister-wife Isis, who has taken the form of a hawk—on the lid of this granite sarcophagus from Abydos, dating to the 26th Dynasty (664‒525 B.C.E.). In Egyptian myth, after the god Osiris is murdered and dismembered, Isis reassembles his body, restores him to life, becomes pregnant and gives birth to their child: the god Horus. To preserve divine dignity, Isis is depicted in the form of a kite as she couples with her brother-husband.