The Battle of Gettysburg, fought from July 1 to July 3, 1863, was a significant turning point in the American Civil War. It marked the first major defeat of Confederate General Robert E. Lee's invasion of the North, halting the momentum of the Confederate Army. The battle resulted in approximately 51,000 casualties, solidifying the resolve of the Union and strengthening President Abraham Lincoln’s administration. Additionally, it led to a shift in public sentiment, with Lincoln's subsequent Gettysburg Address reinforcing the principles of liberty and equality. This battle is often credited with ensuring that the Union retained its resolve to prevail in the war.