For this reason Gumilev attributes the taking of Tiflis to the Khazars.[17] There are good reasons for believing that this success encouraged Tong Yabghu to grander designs. This time he planned to incorporate Aghvania into his khaganate, rather than to wield a usual campaign of plunder. Before returning to Suyab he instructed Böri Shad and his generals to "spare the lives of the rulers and nobles of that land, in as much as they come out to meet my son, surrender to my rule, concede their towns, castles, and trade to my troops".[18]