The Welsh flag we know today officially became the national flag on the 23rd of February 1959, but few know the story of its evolution from ancient times.

It's believed the Romans first brought the dragon emblem to what is now Wales, in the form of the Draco (Latin for serpent or dragon) standards carried by Roman cavalry units. The Draco itself originated with the Sarmatians (a tribe that lived in the area that is now Iran), a unit of whom were stationed as part of the Roman army in Britain from the 2nd to 4th centuries AD.

The oldest known use of the dragon to represent Wales is from the Historia Brittonum, which is commonly attributed to the Welsh monk Nennius around 830.  The text describes a struggle between two serpents who prevent King Vortigern from building a fortress.  This story was later adapted by Geoffrey of Monmouth in Historia Regum Britanniae (c.1136) into a prophecy by Merlin that the white dragon, representing the Saxons, would at first dominate but eventually be conquered by the red dragon, symbolising the Celts. Geoffrey also tells us that King Arthur used a golden dragon banner.

In 1400 Owain Glyndwr raised a banner with a gold dragon on a white background during his revolts against the occupation of Wales by the English crown. Henry VII's flag at the Battle of Bosworth Field in 1485 incorporated a red dragon, which he attributed to Cadwaladr, King of Gwynedd (c.655 to 682 AD) against a background of the Tudor colours green and white. The dragon motif was then incorporated into the Tudor royal arms to signify its Welsh descent.