During the American Civil War, Whitworth's polygonally rifled Whitworth rifle was successfully used by the Confederate States Army marksmen (known as the Whitworth Sharpshooters) to terrorize Union Army artillery crews. The muzzle-loading Whitworth rifle is often called the "sharpshooter" because of its superior accuracy compared to other rifled muskets of its era (far surpassing the breechloading Sharps rifle used by the Union Army), and is considered one of the earliest examples of a sniper rifle. The Whitworth Sharpshooters killed multiple high-ranking Union officers, most famously Maj Gen. John Sedgwick, who was fatally shot at a range of during the Battle of Spotsylvania Court House.