E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A bird, said to be very salacious, hence a prostitute or courtesan.
Heres Agamemnon, an honest fellow enough, and one that loves quails.Shakespeare: Troilus and Cressida, v. 1.
The Iliad of Homer is based on the story that Agamemnon, being obliged to give up his mistress, took the mistress of A chilles to supply her place. This brought about a quarrel between Agamemnon and Achilles, and A chilles refused to have anything more to do with the siege of Troy.