- For the genus of noctuid moths, see Zethes (moth).
- For the social fraternity nicknamed "Zetes", see Zeta Psi
The Boreads (Ancient Greek: Βορεάδαι) are the "wind brothers" in Greek mythology. They consist of Calaïs (Κάλαϊς) and Zetes (also Zethes) (Ζήτης). Their place of origin was Thrace, home of their father Boreas (North wind).
Calais and Zetes were credited to have very delicate and graceful hairs which were said to give them the ability of flying. They had the biggest pride to the longest curls between the two of them and by boasting about these locks, they were very uplifted.
Due to being sons of the north wind they were supernaturally gifted in different ways (depending on changes in the story from being passed down through generations and cultures) either being as fast as the wind or able to fly, having wings either on their feet or backs, depending on the myth.*:I, 211–223
They were Argonauts and played a particularly vital role in the rescue of Phineus from the harpies. They succeeded in driving the monsters away but did not kill them, at a request from the goddess of the rainbow, Iris, who promised that Phineas would not be bothered by the harpies again. As thanks, Phineas told the Argonauts how to pass the Symplegades. It is said that the Boreads were turned back by Iris at the Strophades. The islands' name, meaning "Islands of Turning", refers to this event.:I, 240–300
Calais in one tradition is said to be the beloved of Orpheus; Orpheus was said to have been killed at the hands of jealous Thracian women whilst he wandered the countryside thinking of Calais.
Other sources imply that the sons of Boreas died chasing the harpies, as it was fated that they would perish if they failed to catch those they pursued. In some versions, the harpies drop into the sea from exhaustion and so their pursuers fall as well.
According to a rare variant of the myth by Tzetzes, the old man Phineus who was blind because of old age had two daughters named Eraseia and Harpyreia. These two lived in a very libertine and lazy life which was all wasted. Ultimately, the sisters abandoned themselves into poverty and fatal famine and were eventually snatched away by Calais and Zetes, disappearing from those places ever since.
The Boreads appear in The Heroes of Olympus series by Rick Riordan, where they reside in Quebec City with their sister Khione and their father Boreas. After their death, their father Boreas transformed them into immortal demigods to act as his lieutenants. In the novels, Calais (referred to as "Cal") struggles with words that have more than two syllables, including his own name. He has an obsession with ice hockey and pizza. Zetes is by far the more intelligent of the two, though he has his own quirks as well. He is metrosexual and tries to woo the character Piper McLean each time he encounters her. Both Boreads are teenaged, with purple wings and silvery hair; possess a deep-seated respect for anyone named Jason (because of their role as Argonauts); and carry jagged bronze swords. The two assist their sister Khione in her bid for power, but do not ultimately ally themselves with Gaea.
- John Tzetzes. Chiliades, 1.7 lines 210-213 & 12.13 lines 442-443
- Apollonius Rhodius, Argonautica 
- Katherine Crawford (2010). The Sexual Culture of the French Renaissance. Cambridge University Press. p. 28. ISBN 978-0-521-76989-1.
- John Block Friedman (2000-05-01). Orpheus in the Middle Ages. Syracuse University Press. p. 9. ISBN 978-0-8156-2825-5.
- Phanocles, The Death of Orpheus
- John Tzetzes. Chiliades, 1.7 line 217
- John Tzetzes. Chiliades, 1.7 lines 218-227
- Riordan, Rick (2010). The Lost Hero. New York, New York: Disney-Hyperion. ISBN 978-1-4231-1339-3.
- Riordan, Rick (2014). The Blood of Olympus. New York, New York: Disney-Hyperion. ISBN 978-1-4231-4673-5.