Taliesin is a name like Arthur and Merlin (Myrddin). It has been around for a long time to say the least. I believe the following poem called the Hanes Taliesin tells us the story of the Merovingians back to a time even before Melchizedek.

Hanes Taliesin

1. An impartial Chief Bard
Am I to Elphin.
My accustomed country
Is the land of the Cherubim.

2. Johannes the Diviner
I was called by Merddin,
At length every King
Will call me Taliesin.

3. I was nine months almost
In the belly of the hag Ceridwen;
I was at first little Gwion,
At length I am Taliesin.

4. I was with my Lord
In the highest sphere,
When Lucifer fell
Into the depths of Hell.

5. I carried the banner
Before Alexander.
I know the names of the stars
From the North to the South.

6. I was in Caer Bedion
Tetragrammaton;
I conveyed Heon [the Divine Spirit]
Down to the vale of Ebron.

7. I was in Canaan
When Absalom was slain;
I was in the Hall of D