For the identity of Virtha and Tecrit, see d'Anville, Geographie Ancienne, tom. ii. p. 201. For the siege of that castle by Timur Bec, or Tamerlane, see Cherefeddin, 1. iii. c. 33. The Persian biographer exaggerates the merit and difficulty of this exploit, which delivered the caravans of Bagdad from a formidable gang of robbers.