Proteus is a Greek god of the sea who is capable of changing his form at will. This association explains the word “protean,” which is used to describe something extremely flexible or ever-changing. Though this god is not as well-known as some members of the Greek pantheon, he appeared in a few Greek myths, and his name suggests that he may be quite old, given that protos means “first” in Greek.
According to legend, Proteus is the son of Poseidon and Tethys, and his official job is as the herdsman of Poseidon’s seals on the island of Lemnos. He often appears in the form of a bull seal, looking after the cows in the herd. However, Proteus is also capable of seeing into the future, so he is a form of oracle, which would have made him a figure of reverence in Greek mythology. He also has three children, Polygonos, Telegonos, and Eidothea, who appear periodically in myths alongside and separate from their father.
Homer described Proteus as the “old man of the sea,” describing his formidable oracular powers. However, according to Homer, his abilities came at a price. The god would only tell the future to someone who was able to capture and hold him, and his shape-shifting abilities could make this quite a challenge. Only after being bested would Proteus agree to tell the future or help people, but his advice was typically sound, because he was obliged to tell the truth.
Several Greek heroes apparently went to Proteus for help with various problems, ranging from atoning for offenses against the gods to fixing blights on crops and livestock. Menelaus, for example, allegedly learned of the death of Agamemnon from him, and Proteus also helped him when he was becalmed by the other gods.
Because the idea of being able to change shape at will is both intriguing and appealing to many people, Proteus often appears in works of poetry and fiction, and sometimes characters based on him show up in films, as well. Characters with Protean abilities are typically portrayed as extremely powerful, whether they are villains or heroes, as shape shifting has a wide number of uses, and qualities such as flexibility and ingenuity are often viewed as positive character traits.
Another character named Proteus also appears in Greek mythology. He is a king of Egypt, and he is not related to the god.