From the earliest days of warfare, identification systems were visual and developed into extremely elaborate suits of armour with distinctive heraldic patterns. During the Napoleonic Wars, Admiral Nelson ordered that ships under his command adopt a common paint scheme to reduce friendly fire incidents; this pattern became known as the Nelson Chequer. Invasion stripes served a similar function during the Allied invasion of Normandy in World War II. When radar was developed during World War II, IFF systems to identify aircraft developed into a multitude of radio beacons.