The Dacian Draco [draˈko] was the standard ensign of troops of the ancient Dacian people, which can be seen in the hands of the soldiers of Decebalus in several scenes depicted on Trajan's Column in Rome, Italy. It has the form of a dragon with open wolf-like jaws containing several metal tongues. The hollow dragon's head was mounted on a pole with a fabric tube affixed at the rear. In use, the draco was held up into the wind, or above the head of a horseman, where it filled with air and gave the impression it was alive while making a shrill sound as the wind passed through its strips of material.
Draco (Latin) and Drakon (Greek) mean "serpent", "dragon". The root of these words means "to watch" or "to guard with a sharp eye". It is a derivative of Greek drakōn "gazing" .
The origin of the standard is unknown and still a matter of dispute among scholars. A specific and certain origin is still difficult to be determined. Dacian, Thracian, Scythian, Sarmatian or Parthian origins have been proposed in dedicated historiography. According to Lucreţiu Mihăilescu-Bîrliba by the 2nd century AD, i.e. after the conclusion of the Dacian Wars, the draco symbol was assimilated in the Greco-Roman world with the Dacian ethnos. According to Jon N. C. Coulston the Romans associated this standard with 1st and 2nd century Danubian barbarians. The Roman historian Arrian wrote that the Romans took the draco from the Scythians, most probably a term for the contemporary Sarmatians. It is possible that the serpent or dragon theme was the result of early cartography of the Carpathian mountain range, which resembles a dragon or serpent, facing the west with its tail the black sea.
The original purpose was probably to provide wind direction for archery.
Among the Dacians, the draco was undoubtedly seen by the army as a special protective symbol, while it also played an important role in the religious life of the people.