Abu Salih Mansur (; died 13 June 976), better known as Mansur I () was amir of the Samanids from 961 to 976. The son of Nuh I (), his reign was characterized by weak rule and perpetual financial troubles. Mansur was notably the first Samanid ruler to the use title of King of Kings (Shahanshah), most likely as a response to his rival, the Buyid ruler Adud al-Dawla, who likewise used the title. He is also known by the sobriquet ('The Righteous/Just Emir'). Rise to power Since the reign of Nuh I (), several difficulties started appearing in the Samanid realm, namely financial shortcomings, dissatisfaction in the army, and the emergence of powerful neighbouring kingdoms such as the Buyids. Internal strife, lack of capable viziers and the increasing authority of the Turkic slave-soldiers (ghilman) had also weakened the Samanid realm. The death of Mansur's brother 'Abd al-Malik I at the end of 961 caused a succession crisis. The ghilman, who were effectively in control of the government, split over who should succeed 'Abd al-Malik. Alptigin, the leader of the ghulams and the governor of Khurasan, supported 'Abd al-Malik's son, while Fa'iq Khassa, who had known Mansur since his childhood, pressed for the latter's coronation. Mansur and Fa'iq were eventually victorious; Alptigin fled to Ghazna, which became a separate domain where the Ghaznavid dynasty was eventually formed. The Samanid kingdom was in a dire state after Abd al-Malik's death, according to Narshakhi; "When they buried him, the army grew restless and rebelled; everyone coveted the kingdom, and troubles raised their head." Regardless, the modern historian Clifford Edmund Bosworth states that "Mansur's reign may be regarded as the last one in which the fabric of the empire held firm, such that its prosperity excited favorable comment from outsiders." Reign In order to trace and kill the rebellious Alptigin, Mansur I appointed Abu Mansur Muhammad as the governor of Khorasan, whom he sent against Alptigin. However, Abu Mansur did not manage to kill Alptigin, who fled to Balkh. Abu Mansur, who feared the wrath of his master, shortly changed his allegiance to the Buyid ruler Rukn al-Dawla. Mansur quickly appointed Abu'l-Hasan Muhammad Simjuri as the new governor of Khorasan, and sent him to deal with the rebellious Abu Mansur, which he managed to accomplish. After having brought stability in Khurasan, Abu'l-Hasan Muhammad Simjuri soon went to war with the Buyids, who had