
InGreek mythology,Aesacus orAisakos (/ˈiːsəkəs/;Ancient Greek:Αἴσακος) was a son of KingPriam ofTroy. Aesacus sorrowed for the death of his wife or would-be lover, a daughter of the riverCebren, and was transformed into a seabird.

TheBibliotheca makes Aesacus son of Priam's first wifeArisbe, daughter ofMerops.[1] Apollodorus andTzetzes also make Aesacus a seer who has learned the interpretation of dreams from his grandfather Merops.[2] For them Aesacus is the interpreter ofHecabe's dream when Hecabe gives birth toParis. In Apollodorus the deceased daughter of Cebren for whom Aesacus mourns is his wife named Asterope.

InOvid'sMetamorphoses, Aesacus is an illegitimate son of King Priam secretly born to the nymphAlexirhoe, daughter of theriver Granicus. Aesacus avoidsIlium, preferring the countryside. One day he catches sight of the nymph Hesperia, daughter of the riverCebren, falls in love, and pursues her. However, as Hesperia flees, a venomous snake strikes her and she dies. Aesacus, unable to bear living any longer, leaps from a tall cliff into the sea but as he plunges he is changed into a bird byTethys. Aesacus still attempts to dive into the depth yet continues still to live in the form of a diving bird.[3] The exact identity of the bird, referred to asmergus (later taken as the genus name formerganser ducks) is now unknown, though it has been interpreted as either referring to acormorant or toScopoli’s shearwater.[4][5][6]
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