The extinction of the Iberian royal dynasties, such as Guaramids and the Chosroids, and also the Abbasid preoccupation with their own civil wars and conflict with the Byzantine Empire, led to the Bagrationi family's growth in prominence. The head of the Bagrationi dynasty Ashot I of Iberia (r. 813–826), who had migrated to the former southwestern territories of Iberia, came to rule over Tao-Klarjeti and restored the Principate of Iberia in 813. The sons and grandsons of Ashot I established three separate branches, frequently struggling with each other and with neighbouring rulers. The Kartli line prevailed; in 888 Adarnase IV of Iberia (r. 888–923) restored the indigenous royal authority dormant since 580. Despite the revitalization of the Iberian monarchy, remaining Georgian lands were divided among rival authorities, with Tbilisi remaining in Arab hands.