Roman: Maridunum | Welsh: Caerfyrddin, Caerfyrddyn

A town in Dyfed, on the river Tywi, that can rightly claim to be one of the oldest towns in Wales, probably beginning life as a Celtic hill fort that was obliterated by the Romans, who built a wooden fort there in AD 75. This was the most westerly of their large forts, but few traces remain. However, the discovery of an amphitheatre with a seating capacity of 500 would seem to suggest that the garrison at Carmarthen was not insignificant.

The town was the alleged birthplace of Myrddin and is actually known in Welsh as Caerfyrddin, 'the city of Myrddin'. It is linked to Myrddin, the prototype of Merlin in Welsh tradition, as the Welsh incarnation of the townís name was Caer Myrddin.

Some suggest that Myrddin took his name from the town, while others say that it was named after him. Whatever the truth, the link between the two reached Geoffrey of Monmouth, who made Carmarthen the site of the young Merlinís encounter with King Vortigernís soldiers, on a quest to find a 'fatherless' child. Geoffrey also names Eli as the town provost under the king. Nennius had formerly placed the same events in Elledi. In Layamon, we are told that Uther Pendragonís smith, Griffin, had his forge in Carmarthen.

The town certainly has many connections with this famous wizard, better known as Merlin, and his prophecies. Probably the best known of these is that concerning the Priory Oak, or Merlin's Tree. Myrddin prophesied that the town would fall if this particular tree ever fell. Its remains now stand in the foyer of Saint Peter's Civic Hall, because the tree was moved in 1978 by the local authority from its site in the town, since it consisted mainly of concrete and iron bars and this constituted a hazzard to traffic. Carmarthen, however, is still awaiting the fulfiment of he prophecy, but perhaps simply moving the tree was not enough to bring about the town's downfall.

When Myrddin's tree shall tumble down,
Then shall fall Camerthen town.

About two miles east of Carmarthen, it is believed in legend that Merlin is still alive and lives inside a cave called "Bryn Myrddyn", Merlin's Cave.

It is said that here he is held in bonds of enchantment by Vivienne (Viviane), the woman that he truly loved an who ultimately was to enchant him with the use of his own knowledge bestowed upon her.

The name Carmarthen is an Anglicised form of Caerfyrddyn. There are some who supports the theory of Myrddin being the one whom the town are called after. The Romans called it Maridunum.