'Adud al-Dawla
Abu Tahir Firuzshah was the son of Adud al-Dawla and a daughter of Manadhar, who was a Justanid king. Following 'Adud al-Dawla's death in 983, his possessions were divided between his sons. Samsam al-Dawla, who was the presumed successor of 'Adud al-Dawla, took power, but Sharaf al-Dawla took advantage of his position in Kerman to invade Fars. This invasion distracted Samsam al-Dawla and gave Abu Tahir Firuzshah the ability to set up his own independent rule in Basra, where he took the title of "Diya' al-Dawla".