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.
This name has been borne by two kings of the Franks, two dukes of Normandy, and three kings of Scotland, including Robert the Bruce who restored the independence of Scotland from England in the 14th century. Several saints have also had the name, the earliest known as Saint Rupert, from an Old German variant. The author Robert Browning (1812-1889) and poets Robert Burns (1759-1796) and Robert Frost (1874-1963) are famous literary namesakes. Other bearers include Robert E. Lee (1807-1870), the commander of the Confederate army during the American Civil War, and American actors Robert Redford (1936-), Robert De Niro (1943-) and Robert Downey Jr. (1965-).