But Grant was only a brigadier-general of volunteers, in no way entitled to plan campaigns or to make suggestions for campaigns. Halleck had command of the department, with headquarters at St. Louis. Halleck was a major-general in the regular army and Grant's "superior officer." Halleck disliked, distrusted and detested Grant, and so when Grant asked permission to move against and reduce the Confederate strongholds on the Tennessee and Cumberland rivers, Halleck's reply was in effect an injunction to the inferior officer to mind his own business. Grant was so sure, however, of his ability to accomplish this vitally important task that he persisted in his entreaties and many weeks were consumed in fruitless negotiations for the privilege of doing great work in a great way. At last through the influence of Commodore Foote, commanding the naval forces in that quarter, the discredited volunteer general was graciously permitted by his martinet superior to undertake and execute the first operation of the war which crowned the Federal arms with a victory of strategic importance. This permission, though long solicited, did not come to Grant until the very end of January, 1862, and it was in February that the combined land and naval forces moved for the capture of the Confederate strongholds. The expedition moved first up the Tennessee river. Grant had about 15,000 men, a force which was presently swelled by reinforcement to 27,000. But his advance was delayed and the fleet, with scarcely any assistance from him, captured Fort Henry on the sixth of February. Then the gunboats steamed down the river to its mouth and thence up the Cumberland to assail Fort Donelson. In the meanwhile Grant pushed across the narrow neck of land between the two fortresses and closely invested that fort. The fleet made a determined assault but was beaten off in a badly crippled condition. Grant continued to assail the enemy's works throughout three days of storm and sleet and suffering, and at the end of that time the fortress surrendered with about fourteen thousand men in addition to a Confederate loss in killed and wounded of about two thousand. The greater part of the garrison had previously escaped.