Lee's Army of Northern Virginia suffered a devastating defeat at the Battle of Gettysburg in July 1863. Over the three day battle, Lee launched multiple assaults on the Union flanks and center, including the famous Pickett's Charge on July 3rd, but was unable to break the Union lines. The failed charge resulted in heavy Confederate casualties and marked a turning point from which the Confederacy struggled to recover. Lee was forced to retreat from Gettysburg, dealing a significant blow to the Confederate cause.