The Deev-bend and Persian Hercules, famous for his victory over the white dragon named Asdeev. He was the son of Zâl, prince of Sedjistan. The exploits attributed to him must have been the aggregate of exploits performed by numerous persons of the same name. His combat for two days with Prince Isfendiar is a favourite subject with the Persian poets. The name of his horse was Reksh. Matthew Arnold's poem, Sohrab and Rustam, gives an account of Rustam fighting with and killing his son Sohrab.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894