The Arabs then invaded Khorasan, and made a treaty with the kanarang of Tus, Kanadbak. In the treaty Kanadbak agreed to pay tribute to the Arabs while still remaining in control of his territories in Tus. In order to strengthen the weakened Karen family, and to reclaim lost Karenid territory, Burzin, along with another Karenid named Sawar Karin, made resistance to the Arabs and tried to reclaim territory from the Kanārangīyān family.[2] In promise of regaining his lost territories, Kanadbak agreed to aid Abdullah in capturing Nishapur from the Karenid rebels.