Yes, it was a major victory for Lee.
May of 1863
On April 12,1861
Yes.
The CSA won just about every battle and still lost the war. First Manassas, Second Manassas, Shiloh, and Chancellorsville were among many Confederate victories.
Most historians cite the Confederate artillery as one of the significant elements to the Rebel victory at the 1863 Battle of Chancellorsville. After the US Civil War, Union officers agreed with the assessment that Confederate cannon fire helped to defeat the Union at that battle.During the actual battle, the Confederates took advantage of the situation when Federal units left their defensive positions on Hazel Grove. The Rebels immediately moved their own guns there. Cannons from different Confederate units massed 40 to 50 artillery pieces there and effectively fired upon the retreating Union forces. This ended any chances of Union counterattacks.
Chancellorsville
Chancellorsville
Hooker's army beat a hasty retreat back to Washington.
Better tactics, better leadership.
Union General Joseph Hooker had enough troops to win the Battle of Chancellorsville in 1863. His basic plan was to strike at Confederate General Lee's rear while he was still in position near Fredericksburg. Hooker envisioned a formal set piece battle with reversed fronts. Hooker underestimated Lee's brilliant tactics and suffered a defeat. Clearly this was part of the reason he was replaced as the commander of the Army of the Potomac.
This battle, The Battle of Chickasaw Bayou, in late December of 1862, saw the Confederates win. Confederate General Pemberton defeated forces of Union General Sherman. Sherman's attack on the right flank of Pemberton's forces failed, resulting in a loss for the Union.
Partly because a Confederate detachment was wearing blue uniforms, and Northern gunners thought they were friendly forces until too late. The battle was not a walkover.