Wikipedia
In Greek mythology, Tereus was a Thracian king, the son of Ares and husband of Procne. Procne and Tereus had a son, Itys.
Tereus desired his wife's sister, Philomela. He forced himself upon her, then cut her tongue out and held her captive so she could never tell anyone. He told his wife that her sister had died. Philomela wove letters in a tapestry depicting Tereus's crime and sent it secretly to Procne. In revenge, Procne killed Itys and served his flesh in a meal to his father Tereus. When Tereus learned what she had done, he tried to kill the sisters but all three were changed by the Olympian Gods into birds: Tereus became a hoopoe; Procne became the nightingale whose song is a song of mourning for the loss of her child; Philomela became the swallow, which has no song.
Other versions of this myth have Procne transformed into the swallow and Philomela into a nightingale ( Hyginus, Fabulae, 45).
Tereus was also a common given name among Thracians.
The Attic playwrights Sophocles and Philocles both wrote plays entitled Tereus on the subject of the story of Tereus.
Shakespeare refers to Tereus in Titus Andronicus, after Chiron and Demetrius have raped Lavinia and cut out her tongue and also both her hands.
Tereus (, Tēreus) is a Greek play by the Athenian poet Sophocles. Although the play has been lost, several fragments have been recovered. Although the date that the play was first produced is not known, it is known that it was produced before 414 BCE, because the Greek comedic playwright Aristophanes referenced Tereus in his play The Birds, which was first performed in 414. Thomas B. L. Webster dates the play to near but before 431 BCE, based on circumstantial evidence from a comment Thucydides made in 431 about the need to distinguish between Tereus and the King of Thrace, Teres, which Webster believes was made necessary by the popularity of Sophocles play around this time causing confusion between the two names. Based on references in The Birds it is also known that another Greek playwright, Philocles, had also written a play on the subject of Tereus, and there is evidence both from The Birds and from a scholiast that Sophocles' play came first.
Some scholars believe that Sophocles' Tereus was influenced by Euripides' Medea, and thus must have been produced after 431. However, this is not certain and any influence may well have been in the opposite direction, with Sophocles' play influencing Euripides. Jenny Marsh believes that Euripides' Medea did come before Sophocles' Tereus, based primarily on a statement in Euripides' chorus "I have heard of only one woman, only one of all that have lived, who put her hand on her own children: Ino." Marsh takes this to imply that as of the time of Medea's production, the myth of Tereus had not yet incorporated the infanticide, as it did in Sophocles' play.