A Dictionary of Greek and Roman biography and mythology

(Ἕρκυνα), a divinity of the lower world, respecting whom the following tradition is related. She was a daughter of Trophonius, and once while she was playing with Cora, the daughter of Demeter in the grove of Trophonius, near Lebadeia in Boeotia, she let a goose fly away, which she carried in her hand. The bird flew into a cave, and concealed itself under a block of stone. When Cora pulled the bird forth from its hiding place, a well gushed forth from under the stone, which was called Hercvna. On the bank of the rivulet a temple was afterwards erected, with the statue of a maiden carrying a goose in her hand; and in the cave there were two statues with staves surrounded by serpents, Trophonius and Hercyna, resembling the statues of Asclepius and Hygeia. (Paus. 9.39.2.) Hercyna founded the worship of Demeter at Lebadeia, who hence received the surname of Hercyna. (Lycoph. 153, with the note of Tzetzes.) Hercyna was worshipped at Lebadeia in common with Zeus, and sacrifices were offered to both in common. (Liv. 45.27.)

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