Answer
Less than a year, Al-Husayn ibn al-Qasim served a short tenure as vizier due to his tumultuous relationship with the caliph, Al-Musta'in. Appointed in December 865, he faced difficulties in appeasing both the caliph and the Turkish military leaders. His policies, such as reducing military stipends, sparked discontent among the influential Turkish military establishment. Ultimately, these challenges led to his dismissal in September 866, lasting only nine months in office.