911, Sistan was under complete Samanid control, and Ahmad's cousin Abu Salih Mansur was appointed as its governor. Meanwhile, an Alid named Hasan al-Utrush was slowly re-establishing Zaydi over Tabaristan. In 913, Ahmad sent an army under Muhammad ibn Sa'luk to deal with him. Although the Samanid army was much larger, Hasan managed to emerge victorious. Ahmad, before he could plan another expedition to Tabaristan, was the following year murdered by some of his slaves in a tent near Bukhara. During his reign, Ahmad is also said to have replaced the language of the court from Persian to Arabic, which made him unpopular among his subjects, and forced him to change it back to Persian. After Ahmad's death, his eight-year-old son Nasr II (r. 914–943) succeeded him. Due to Nasr's youth, his prime minister Abu 'Abd-Allah al-Jaihani took care over most of the state affairs. Jaihani was not only an experienced administrator, but also a prominent geographer and greatly educated man. Almost right after Nasr II had ascended the throne, several revolts erupted, the most dangerous one being under his paternal grand-uncle, Ishaq ibn Ahmad, who seized Samarkand and began minting coins there, while his son Abu Salih Mansur seized Nishapur and several cities in Khorasan. Ishaq was eventually defeated and captured, while Abu Salih Mansur died of natural causes in 915. Some time later Nasr II once again had to deal with rebels; in 919, the governor of Khorasan, Husayn ibn Ali Marvarrudhi, rebelled against Samanid authority. Nasr responded by sending an army under Ahmad ibn Sahl to suppress the rebellion, which the latter managed to accomplish. After a few weeks, however, Ahmad shortly rebelled himself at Nishapur, made incursions into Gorgan, and then fortified himself in Merv to avoid a Samanid counter-attack. Nevertheless, the Samanid general Hamuya ibn Ali managed to lure Ahmad out of Merv, and defeated him in a battle at Marw al-Rudh; he was captured and imprisoned in Bukhara, where he remained until his death in 920. In the west, Nasr II clashed several times with Daylamite and Gilite rulers; In 921, the Zaydids under the Gilite ruler Lili ibn al-Nu'man invaded Khorasan, but were defeated by the Simjurid general Simjur al-Dawati. Later in 930, a Dailamite military leader, Makan ibn Kaki, seized Tabaristan and Gurgan, and even took possession of Nishapur in western Khorasan. He was, however, forced to withdraw back to Tabaristan one