THE WELSH FLAG

The ancient poets Aneirin and Taliesin use the Welsh word for dragon "draig" in the sense of "warrior" or "leader" and this usage remained to the Middle Ages. In the Historia Brittonum (ascribed to Nennius) of around 800 A.D. the dragon is seen as a symbol of national independence in the story of the red dragon battling with the white dragon of the Saxon enemy.

At the time of the Norman invasion of England in 1066, the dragon symbol seems to have been used by both sides. The Bayeux tapestry shows king Harold close to a dragon standard as he falls and the dragon also appears on the pennant of one of duke William's messengers.

Despite its occasional use by other figures famous in Welsh history, the red dragon became the symbol of the Welsh nation through its adoption by the Tudor ancestors of king Henry VII. Edmund and Jasper Tudor had a dragon as crest and supporter to the arms granted them by Henry VI. When Henry Tudor faced king Richard III at the battle of Bosworth in 1485 his battle standards numbered three. One of these carried the arms of St. George of England, one the arms of the house of Beaufort and on one was a "Red ffyry dragon peyntid upon white and Grene Sarcenet".  It is held that this dragon banner represented Henry Tudor's claim to be a true representative of the ancient kings of Britain and served as his tribute to the Welsh people who had made his victory possible.

Additional history may be found at
http://www.bbc.co.uk/wales/history/sites/themes/flag.shtml