Although the harbor of Mobile Bay had been closed to blockade running traffic since mid-summer 1864 with Admiral David G. Farragut's victory there, the port city of Mobile still remained in Confederate control. In late March 1865, two Federal infantry columns converged on the defenses of the city at Fort Blakely and Spanish Fort. One force of 13,000 Union soldiers commanded by Gen. Frederick Steele moved west from Pensacola with orders to take Blakely from the rear. Union Gen. Edward R.S. Canby’s Sixteenth and Thirteenth Corps moved north along the eastern shore of the bay in March 1865, forcing Confederates there to fall back north into their defenses . By April 1st, Union forces had enveloped Spanish Fort. Brig. Gen. St. John R. Liddell, with about 4,000 men, held out against the much larger Union force until it fell on April 8th, allowing Canby to concentrate 16,000 men for the attack on Fort Blakely the next day. The Union's overwhelming numbers in both columns eventually breached the Confederate earthworks compelling the Confederates to capitulate, six hours after Robert E. Lee surrendered his army at Appomattox, Virginia. The siege and capture of Fort Blakely was the last combined-force battle of the war. African-American forces played a major role in the successful Union assault.