Which event happened before general lee moved his forces out of pennsylvania in 1863?

The Battle of Gettysburg took place around the town with the same name in 1863 in Pennsylvania, as part of the American Civil War. It became the most costly battle in US history with large number of casualties in both sides. Union forces were leaded by George Meade who could defeat the attacks initiated by the Confederates under the command of General Lee.

After the defeat at Gettysburg, Lee's army retreated to Virginia.