Proto or Protho (Ancient Greek: Πρωτώ) is one of the fifty Nereids, marine-nymph daughters of Nereus and the Oceanid Doris. Her name means "the first" or "the receiver," and she is sometimes glossed as the Nereid of the first or maiden voyage. Hesiod and Homer place her in the sea-sister catalogues; she mourns with Thetis after the death of Patroclus.
Adapted from Wikipedia, "Proto (mythology)" · CC BY-SA 4.0
I.Among the Nereids
Hesiod lists Proto among the daughters of Nereus and Doris in the Theogony — after Agaue and Doto, beside Pherusa and Dynamene. Apollodorus and Hyginus likewise count her among the fifty Nereids.
She is a catalogue name with little standalone myth: her identity is genealogical and etymological, marking firstness or first passage among the better-attested sisters such as Thetis and Amphitrite.
II.In the Iliad
When Thetis cries out for Achilles' grief over Patroclus, Homer names Proto in the bright cave with Doto, Pherousa, and Dynamene among the sisters who beat their breasts at the goddess' lead.
III.Homonyms
This atlas entry (proto-nereid) is strictly the Nereid. She must not be confused with Protogeneia or other mortal figures whose names begin with Proto-.