^Tarn, William Woodthorpe (2010). The Greeks in Bactria and India. Cambridge University Press. pp. 51–52. ISBN9781108009416. ...for earlier Arsacids married their half- sisters or other princesses, and the first king whose mother was a Greek concubine Vologases I, A.D. 57-77; the statement cannot be earlier than his reign.
^Bunson, Matthew (1995). A Dictionary of the Roman Empire. Oxford University Press. p. 454. ISBN9780195102338. VOLOGASES I (d. 80 A.D.) King of Parthia from circa 51 to 80 A.D.; the greatest of the five kings who would bear his name, although Parthia was troubled throughout his reign on both its eastern and western borders. He was the son of VONONES II, a one-time monarch of Media-Atropatene. His mother was reportedly a Greek concubine.