Malik Shah becomes Sultan

Under Alp Arslan's successor, Malik Shah, and his two Persian viziers, Nizām al-Mulk and Tāj al-Mulk, the Seljuk state expanded in various directions, to the former Iranian border of the days before the Arab invasion, so that it soon bordered China in the east and the Byzantines in the west. Malik Shāh was the one who moved the capital from Rey to Isfahan. It was under his rule and leadership that the Seljuk Empire had reached the height of its successes.