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).

Joining together in one of the local alliances between the Christian naxarars and Muslim emirs that was to characterize the history of medieval Armenia, Sahak, prince of western Siwnik‘, the Djahhafid emir and the usually cautious sparapet Smbat, abandoning on this occasion the loyalist tradition of the Bagratuni house toward the caliphate, disregarded the conciliatory intervention of the kat‘olikos Dawit‘ II and defied the ostikan in 831/2 according to the Armenian historian Yovhannes “the Kat'olikos.” (Yovhannes Drasxanakertc‘i, xxv, p. 117). Unfortunately for the rebels, the Prince of Princes Bagarat held aloof with the forces of the south, and the ostikan, taking the initiative of the attack, routed them in a bloody battle on the Hrazdan River north of Duin. Sahak of Siwnik‘ was killed, and his domain passed to his son Grigor Sup‘an I. The Djahhafid emir fled to Siwnik‘ to bring more trouble on the region, and Smbat sparapet took refuge in his northern domains.