shortly after bagrat iv's ascension to the throne, constantine viii sent in an army to take over the key city-fortress of artanuji on behalf of the georgian bagratid prince demetrius, son of gurgen of klarjeti, who had been dispossessed by bagrat iv's grandfather, bagrat iii, of his patrimonial fief at artanuji early in the 1010s. several georgians nobles defected to the byzantines, but bagrat's loyal subjects put up a stubborn fight. the byzantines overran the georgian borderlands and besieged kldekari, a key fortress in trialeti province, but failed to take it and marched back on the region shavsheti. the local bishop saba of tbeti organized a successful defense of the area forcing the byzantines to change their tactics.