The Song military was chiefly organized to ensure that the army could not threaten Imperial control, often at the expense of effectiveness in war. Northern Song's Military Council operated under a Chancellor, who had no control over the imperial army. The imperial army was divided among three marshals, each independently responsible to the Emperor. Since the Emperor rarely led campaigns personally, Song forces lacked unity of command. The imperial court often believed that successful generals endangered royal authority, and relieved or even executed them (notably Li Gang, Yue Fei, and Han Shizhong).