Vicksburg was the ‘nail that holds the South’s two halves together’, according to the Confederate President Jefferson Davis. In early 1863, Ulysses S. Grant attempted lateral thinking to pry the nail loose. He commissioned a series of attempts to build canals over the De Soto peninsula, north of Vicksburg: each would be abandoned. Another foray, the ‘Yazoo Pass’ expedition, first destroyed a levee at Moon Lake, to flood a navigable passage to the Yazoo River. The Confederates harried and sabotaged the expedition, while swiftly building Fort Pemberton to block its path. Three naval assaults on the fort were repulsed (11–16 March), as was a subsequent attempt to bypass it via Steele’s Bayou. Once Grant had finally reached the outskirts of Vicksburg in May, a lightning contrast to all these bog-mired exertions was afforded by General Benjamin Grierson’s 1,000-mile (1,610-km) diversionary cavalry raid through Louisiana.