Dogs in warfare have a very long history starting in ancient times. From being trained in combat, to their use as scouts, sentries, messengers, mercy dogs, and trackers, their uses have been varied and some continue to exist in modern military usage. War dogs were used by the Egyptians, Greeks, Persians, Sarmatians, Baganda, Alans, Slavs, Britons, and Romans. Among the Greeks and Romans, dogs served most often as sentries or patrols, though they were sometimes taken into battle. The earliest use of war dogs in a battle recorded in classical sources was by Alyattes of Lydia against the Cimmerians around 600 BC. The Lydian dogs killed some invaders and routed others. At the Battle of Pelusium (525 BC), Cambyses II deployed dogs, cats, and other animals held sacred by the Egyptians. By putting these animals in the front lines, he was supposedly able to get the Egyptians to cease using their projectile weaponry. During the Late Antiquity, Attila the Hun used large war dogs in his campaigns. Gifts of war dog breeding stock between European royalty were seen as suitable tokens for exchange throughout the Middle Ages. Other civilizations used armored dogs to defend caravans or attack enemies. In the Far East, 15th-century Vietnamese Emperor Lê Lợi raised a pack of over 100 hounds, tended and trained by Nguyễn Xí, whose skills were impressive enough to promote him to the commander of a shock troop regiment. Later on, Frederick the Great of Prussia used dogs as messengers during the Seven Years' War with Russia. Napoleon also used dogs during his campaigns. Dogs were used until 1770 to guard naval installations in France. The first official use of dogs for military purposes in the U.S. was during the Seminole Wars. Hounds were used in the American Civil War to protect, send messages, and guard prisoners. General Grant recounts how packs of Southern bloodhounds were destroyed by Union troops wherever found due to their being trained to hunt runaway slaves before the war. Dogs were also used as mascots in American WWI propaganda and recruiting posters.