The political and commercial importance of New Orleans, as well as its strategic position, marked it out as the objective of a Union expedition soon after the opening of the Civil War. Elements of the Union Blockade fleet arrived at the mouth of the Mississippi on 27 May 1861. An effort to drive them off lead to the Battle of the Head of Passes on 12 October 1861. Captain D.G. Farragut and the Western Gulf squadron sailed for New Orleans in January 1862. The main defenses of the Mississippi consisted of the two permanent forts, Fort Jackson and Fort St. Philip. On April 16, after elaborate reconnaissances, the Union fleet steamed up into position below the forts and opened fire two days later. Within days, the fleet had bypassed the forts in what was known as the Battle of Forts Jackson and St. Philip. At noon on the 25th, Farragut anchored in front of New Orleans. Forts Jackson and St. Philip, isolated and continuously bombarded by Farragut's mortar boats, surrendered on the 28th, and soon afterwards the military portion of the expedition occupied the city resulting in the Capture of New Orleans.