In ancient Rome, Diva Drusilla Panthea was the name under which the emperor Caligula deified his favourite sister, Julia Drusilla (16-38), after her death at age 21. This name was also borne by a mistress of Roman co-emperor Lucius Verus (130-169).
In theatre, it was used by Beaumont and Fletcher for a princess in their play A King and No King (1619) and by Percy Bysshe Shelley for an Oceanid in his play Prometheus Unbound (1820). Oscar Wilde also wrote a poem entitled Panthea (1881). Panthea Vyne was the titular lady in the television film The Lady and the Highwayman (1989), based on Barbara Cartland's historical novel Cupid Rides Pillion (1952).
Notable bearers of this name include the Greek philosopher and mathematician Theon of Smyrna (2nd century AD) and the Greek scholar and mathematician Theon of Alexandria (4th century AD).
In modern literature, this name is best known for being the name of Theon Greyjoy, a character from the A Song of Ice and Fire series of fantasy novels written by the American author George R. R. Martin (b. 1948). He also appears in Game of Thrones (2011-2019), a television series based upon the novels.
As a given name, it has been occasionally used from the 19th century onwards.