A Tale of Two Dragons at Dinas Emrys at King Arthurs Labyrinth

Once upon a time there was a King Gwrtheryn desperately trying to build himself a tower at Dinas Emrys as defence against the invading Saxons. Every morning the stones placed the previous day had disappeared, swallowed into the ground. King Gwrtheryn is told he needs the blood of a fatherless boy to sprinkle over the stones to mix with the mortar - he finds Myrddin (Merlin)... Can Myrddin help?
Merlin is taken to Dinas Emrys and persuades King Gwrtheryn not to kill him but instead to listen to him. Merlin took a deep breath and began his prophecy:
"Beneath the foundations where you are trying to build your tower there is a pool and under the water you will find two hollow stones. In the daytime two dragons sleep, one inside each stone but at night they wake and fight each other. It is because of them that your tower collapses."
King Gwrtheyrn ordered his men to dig and find the pool - they found it. King Gwrtheyrn started to believe that Myrddin did have magical powers. He then ordered his men to drain the pool and just as Merlin had prophesied, two stones lay at opposite ends of the hole.
As they watched a red dragon emerged from one stone and a white dragon from the other and they soon began to fight fiercely. King Gwrtheryn asked Myrddin "what is the meaning of the dragons, my boy". Merlin replied "the dragons represent the battles between the Britons and the Saxons, Sire. The white dragon is the strongest and he represents the Saxons and, for a time, will have the upper hand. But the red dragon represents the Britons who will overcome them under the leadership of a great King named Arthur."