The 1863 Vicksburg campaign was to prove decisive to the outcome of the American Civil War (1861-1865). Known as the 'Gibraltar of the West', Vicksburg was the last Confederate stronghold on the Mississippi River. In a masterly campaign Grant used riverboats and steamers to land his army south of the city. He then defeated the armies of Generals 'Joe' Johnston and John C. Pemberton. Pemberton allowed his force to become bottled up in Vicksburg and after an epic 47-day siege he was forced to surrender the remnants of his force to Grant on 4 July 1863, one day after Lee's defeat at Gettysburg.