The First Battle of Fort Fisher was a naval siege in the American Civil War, when the Union tried to capture the fort guarding Wilmington, North Carolina, the South's last major Atlantic port. Led by Major General Benjamin Butler, it lasted from December 24–27, 1864. The Union navy first attempted to detonate a ship filled with powder in order to demolish the fort's walls but this failed; the navy then launched a two-day bombardment in order to demolish the fort and compel surrender. On the second day, the Union army started landing troops in order to begin the siege. But Butler got news of enemy reinforcements approaching, and in the worsening weather conditions, he aborted the operation, declaring the fort to be impregnable. To his embarrassment, Butler was relieved of command on January 8, 1865, and was replaced by Major General Alfred H. Terry, who led a follow-up expedition that captured the fort one week later. Background After the failed Bermuda Hundred Campaign, Major General Benjamin Butler and his Army of the James were assigned to an amphibious expedition against Fort Fisher. Lieutenant General Ulysses S. Grant had originally designated one of Butler's subordinates, Major General Godfrey Weitzel, to lead the expedition, but Butler, as the commander of the Department of Virginia and North Carolina, demanded that he lead the troops himself and Grant acquiesced. Units for the expedition were selected from the Army of the James and included the 2nd Division of the XXIV Corps and the 3rd Division from the XXV Corps, along with two battalions of heavy artillery and engineers. Colonel Cyrus B. Comstock from Grant's staff went along to serve as chief engineer. The Union naval expedition under Rear Admiral David D. Porter comprised the largest Union fleet of the war, nearly 60 warships along with the transports to carry the army troops. Butler also planned to bring the , which had been packed with 200 tons of powder and disguised as a blockade runner, down to Fort Fisher, run it aground about a hundred yards from the fort's seawall, and blow it up, hoping the explosion would demolish the fort as well. Although many in the Union high command (including Grant and Gideon Welles) doubted the plan would work, it was approved by Lincoln. The final Union plan was for the ships to gather at Hampton Roads, where the army troops would board the transports.