Scylla, daughter of Nisus.
      Scylla Nisi is a princess of Megara and daughter of King Nisus of Megara. She is most remembered for cutting a lock of her father’s hair which prophetically ensured the protection of his city if left intact. When the Cretan king Minos sieged Megara, Scylla loved to climb to the top of the city walls and watch the enemy warriors. She became enamored with Minos from afar and resolved to betray the city to him so they could be together. [Note that Aeschylus has her succumb to a bribe, a golden necklace.] To do this, she cut off her father’s lock of hair, stole into the enemy camp, and offered the fateful lock to Minos, betraying thereby her homeland and guaranteeing Minos’ victory. However, Scylla’s treachery utterly alienated his affection, and Minos sailed away, either abandoning the despised girl or, in some versions, punishing her treachery by binding her to the ship’s prow. Some distance across the Saronic Gulf, Scylla was metamorphosed into the ciris bird — an aetiological pun (κείρειν = “to shear”) — which is engaged in relentless ornithological battle with the metamorphosed Nisus, the haliaeetus (sea-eagle).
      Although Ovid’s account of Scylla Nisi in Metamorphoses 8 is the best known classical narrative, numerous fragmentary Scylla narratives in Hellenistic authors from Callimachus to Parthenius suggest that hellenistically inclined poets of Rome’s literary golden age were intrigued by the myth’s intertextual opportunities. The pseudo-Vergilian Ciris alone of surviving sources attributes Scylla’s treachery to the wiles of her nurse Carme (mother of Britomartis-Dictynna).
      In Hellenistic and, especially, in Roman literature, Scylla was depicted as a sea nymph romantically pursued by the sea god Glaucus. Ovid’s Scylla spurned Glaucus’ advances, and he sought aid from the titaness/witch Circe to make Scylla love him. Circe, who fell in love with Glaucus, in jealousy toward Scylla, transformed the sea nymph into a sea monster of epic proportions. Roman literary sources beginning with Vergil tell Scylla’s metamorphosis to a maiden with dogs girding her waist, the curse of Circe. In European iconographic tradition, Scylla is frequently depicted just before dogs assail her, i.e. as a maiden bathing in Circe’s poisoned water. Even in classical sources, but especially in the later tradition, Scylla is transformed into the foreboding headland at Castel Ruffo on the Calabrian side of the Messina Strait, a dangerous geological obstacle to passing sailors.
      NB: Scylla Crataeis is sometimes equated or conflated with the princess of Megara, also named Scylla (or, Scylla Crataeis/Scylla the daughter of Crataeis).
— RTM with Al G, Grace W, Katie J, Abby M


Further Reading:
G.M.A. Hanfmann (1987), “The Scylla of Corvey and Her Ancestors,” Dumbarton Oaks Papers 41:249-60. — JSTOR

Lexicon Iconographicum Mythologiae Classicae (1997) VIII.1.1137-45 s.v. "Skylla I", with plates at VIII.2 [Jentel, Marie-Odile].

Lexicon Iconographicum Mythologiae Classicae (2009) “Skylla I [addendum],” Supplementum 2009 1.453-57, with plates.

Hopman, Marianne Govers. 2012. Scylla: myth, metaphor, paradox. Cambrige University Press. — https://www.google.com/books/edition/Scylla/

Carbone, Marco Benoît. 2022. Geographies of Myth and Places of Identity: the Strait of Scylla and Charybdis in the modern imagination. London: Bloomsbury.


See also:
      Glaucus
      Odysseus: Scylla and Charybdis