Ahmad ibn Buya (Persian: احمد بن بویه, died April 8, 967), after 945 better known by his laqab of Mu'izz al-Dawla (Arabic: معز الدولة البويهي, "Fortifier of the Dynasty"), was the first of the Buyid emirs of Iraq, ruling from 945 until his death.

Ahmad overran much of Kerman, but encountered resistance from the Baluchis and Arab Qafs,[4] receiving a wound to the head and losing a hand and several fingers on the other.

News of this event was received negatively by the Hamdanid amir Nasir al-Dawla, who ruled over Mosul and the districts of the eastern Jazira.

Mu'izz al-Dawla, on the other hand, was on less secure ground; Baghdad was in a sorry state thanks to years of mismanagement and he was hamstrung by its numerous financial and military problems.

[11] As a result, Nasir al-Dawla took a belligerent tone with the Buyids: he withheld the payment of tribute to Baghdad,[12] refused to recognize al-Muti' as caliph and continued to mint coins in al-Mustakfi's name.

In February 946, Mu'izz al-Dawla sent an army under the command of Musa Fayadhah and Yanal Kushah to Ukbara, in preparation for a campaign to conquer Mosul.

[14] While stationed at Samarra, Nasir al-Dawla sent his brother Jubayr to sneak around the Buyid army and head south to Baghdad.

When Jubayr arrived at the city, he was welcomed by the citizens and by Mu'izz al-Dawla's former secretary Muhammad ibn Shirzad, who declared his allegiance to the Hamdanids and administered the affairs of Baghdad on their behalf.

[15] When Mu'izz al-Dawla learned that he had lost Baghdad, he gathered his Daylamite soldiers, who had been busy plundering Tikrit and Samarra, and headed back to the city.

Getting troops across the Tigris successfully was a challenge, and even if an army managed to make it to the opposite shore, they were usually forced to retreat in short order.

Each day, Ibn Shirzad led a number of zabzabs filled with Turks up and down the Tigris, and they shot arrows at the Daylamites stationed on the western side of the city.

[19] On the eastern side, Nasir al-Dawla attempted to legitimize his seizure of the city by re-issuing the coinage of 942–943, from when he had last been in control of Baghdad.

Ibn Shirzad was also able to augment the ranks of the Hamdanid forces by enlisting local citizens and criminals, and they participated in attacks on Mu'izz al-Dawla's Daylamite troops.

Eastern Baghdad was able to avoid any serious shortages thanks to shipments flowing down from Mosul, but the western side was subjected to a blockade for the duration of the conflict.

[22] By July 945, with no end to the battle in sight and with the blockade making supplies increasingly scarce, Mu'izz al-Dawla was giving serious thought to abandoning western Baghdad and retreating to al-Ahwaz.

[23] He eventually decided to make one final attempt to take the eastern side, and if the effort failed he would give the order to withdraw.

He gave orders to his chief secretary Saymari to cross to the eastern bank with a number of handpicked Daylamites, while he himself would attempt to distract the Hamdanid forces with a ruse.

Nasir al-Dawla, realizing that he was in danger of losing the city, ordered Ibn Shirzad to take command of the troops and push the Daylamites back across the river.

Nasir al-Dawla then realized that the fight was lost and joined the retreat; the Hamdanid forces withdrew from Baghdad and allowed the Buyids to take control of the city.

Ignoring an order by Mu'izz al-Dawla to refrain from pillaging, they began looting, set fire to houses and killed a number of civilians.

Mu'izz al-Dawla agreed to recognize the Hamdanid as ruler of the territory from Tikrit northwards, and to release him from the obligation of transmitting tax revenues from Mosul and the Diyar Bakr district.

In exchange, Nasir al-Dawla agreed to recommence the payment of tribute for the Jazira and Syria, as well as to add the names of the three Buyid brothers after that of the Caliph in the Friday prayer.

The title of "Taj" ("crown") implied that Fana-Khusrau was superior to his father and uncle, provoking a reaction from Mu'izz al-Dawla.

A false rumor of Mu'izz al-Dawla's death in 955, however, prompted 'Imran to seize a Buyid convoy traveling from Ahvaz to Baghdad.

While Mu'izz was preoccupied with the rebellion of his Daylamite troops under Ruzbahan in southern Iraq, Nasir al-Dawla used the opportunity to advance south and capture Baghdad.

[28][31] Peace was renewed in exchange for the resumption of tribute and an additional indemnity, but when Nasir al-Dawla refused to send the second year's payment, the Buyid ruler advanced north.

The Buyids captured Mosul and Nasibin, but the Hamdanids and their supporters withdrew to their home territory in the mountains of the north, taking with them their treasures as well as all government records and tax registers.

As a result, the Buyid army was unable to support itself in the conquered territory, all the more so since the predominantly Daylamite troops were resented by the local people, who launched guerrilla attacks on them.

The Sunni Turks, who found their privileges eroded by the Daylamite troops that had entered Baghdad with their master in 945, constantly threatened to upset the internal stability of the state.

Mu'izz al-Dawla at first favored the Daylamite troops but later attempted to compromise between the two groups, making a Turk named Sebük-Tegin his chief commander.