Hovannisian R. G. The Armenian People from Ancient to Modern Times. — Basingstoke: Palgrave Macmillan, 1997. — Vol. I. The Dynastic Periods: From Antiquity to the Fourteenth Century. — P. 137. — 386 p. — ISBN 0-312-10169-4, ISBN 978-0-312-10169-5.The alliance with Babek was not always advantageous for Siwnik‘, as we shall see, and after Vasak’s death in 821 his lands were divided between his two sons: Sahak, prince of western Siwnik‘ or Gelakunik‘ (Geghakunik), with the famous religious and intellectual center of Makenoc‘ (Makenots) Vank, and P‘ilippos, prince of eastern Siwnik‘ or Vayoc‘ Jor (Vayots Dzor) (modern Eghegnadzor), southeast of Lake Sevan, where the local dynasts were to erect the still more distinguished monastic center of Tat‘ew (Tatev).