"Wales" as a cohesive land didn't exist until Llywelyn ap Gruffydd, Prince of Gwynedd and the ruler of Deheubarth, claimed himself Prince of Wales in the 13th century. The lands of Llywelyn being conquered by Edward I of England and becoming part of England. Wales was then properly established as a single principality about 20 years later when the Kings son was given the title Prince of Wales. So the "Welsh" dragon, unless it's older than Wales can't really be Homeric in origin. Now that Welsh dragon might have been used previously by the Princes of Gwynedd, Powys Deheubarth, etc.. but that's another story.
-- by me on 2008-01-04, pbhj