Fahrü'd-Devle b. Büveyh, Ali b. Ruknü'd-Devle Abu Ali Hasan b. Büveyh al-Daylamī. He ruled over the city of Rayy and its surrounding regions. When his brother Muayyadü'd-Devle passed away, the vizier Ibn ʿAbbād wrote him a letter requesting that he come quickly to the center of administration. He immediately went there. After the death of his brother, the vizier Ibn ʿAbbād promptly installed him as ruler. Fahrü'd-Devle retained Ibn ʿAbbād as his vizier.
Fahrü'd-Devle died at the age of forty-six. He spent thirteen years, ten months, and seven days of his life in rulership. He left behind a great fortune. The gold amounted to nearly 3,000,000 dinars. The jewels he left numbered about 15,000 pieces, valued at nearly 3,000,000 gold dinars. Additionally, there were gold vessels weighing 1,000,000 dinars, silver vessels weighing 3,000,000 dirhams, 3,000 loads of fabric and clothing, weapons weighing 1,000 loads, household items and furnishings weighing 1,500 loads, and countless other items worthy of kings.
However, on the night he died, they were unable to obtain his wealth. They could only prepare his shroud by cutting and tailoring it from the clothing of a man who lived adjacent to the mosque. They set him aside and busied themselves with installing the new ruler. Eventually, his son Rustam succeeded him as ruler. Meanwhile, his corpse decomposed. No one dared approach him anymore. They tied him with ropes and dragged him down the castle stairs. Thus, his body was torn apart. This was a fitting punishment for him.