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''. Diya' al-Dawla, as well as another brother,
Taj al-Dawla, who controlled
Khuzestan, eventually decided to acknowledge the authority of
Fakhr al-Dawla, who ruled in
Jibal. This was done in an attempt to protect themselves from the conflict between Samsam al-Dawla and Sharaf al-Dawla; Basra and Khuzestan were situated in between the possessions of the two and were therefore vulnerable. Nevertheless, after a few years Sharaf al-Dawla invaded and occupied Basra and Khuzestan, causing the two princes to flee to Fakhr al-Dawla's territory. There they found refuge in
Ray. Neither of the two brothers managed to found any lasting line; consequently their role in Buyid politics was short. ==References==