There is a small piece of blackened wood in a glass case at the Carmarthenshire County Museum at Abergwili. It looks like nothing - a fragment of dead tree. The local prophecy says that as long as Merlin's Oak stood at the corner of Priory and Old Oak Lane in Carmarthen, the town would not fall. When the oak finally died, in the early 19th century, the townspeople did not take any chances. They dug up what was left of it and kept the pieces. The town is still here. Whether that is because of the prophecy, or because Carmarthen has had nearly two thousand years of practice at not falling, is a question the museum lets you decide for yourself.
The Romans got here in the second century AD and built a fort called Moridunum on a low hill above the navigable reach of the River Towy. They followed it with a small town and, remarkably, an amphitheatre - one of only seven that survive in Britain, and one of just two in Roman Wales. The arena was about 46 by 27 metres, the bowl of seating around it roughly 92 by 67 metres. Today the grassed oval sits in a quiet corner east of the town centre, and at first glance it looks like nothing more than a strange dip in a field. Carmarthen is one of two Welsh towns that can plausibly claim to be the oldest in Wales, and the case here rests on a single principle: people have lived continuously on this hill, with rare interruption, since the Romans left.
By the time Geoffrey of Monmouth wrote in the late 12th century, the Welsh had given the town a different name: Caerfyrddin. The standard translation is 'Merlin's fort,' and Geoffrey duly placed Merlin's birth in a cave just outside the walls. Linguists have argued ever since about which way the influence runs. The town's Roman name, Moridunum, can be read as 'sea fort,' which over centuries of Welsh sound-change might have become Myrddin, and the wizard might have taken his name from the place rather than the other way around. The Black Book of Carmarthen, a roughly 1250 manuscript of Welsh poetry kept at the town's old priory, contains the earliest written references to both Merlin and Arthur in Welsh. Reverse-engineer the etymology however you like; the result is the same. This is the town where the wizard is from.
The Norman castle went up around 1094, built by William fitz Baldwin on the bluff above the river. Llywelyn the Great destroyed it in 1215. The town rebuilt it in 1223, threw a wall around itself, and became one of the first medieval walled towns in Wales. Owain Glyndwr sacked it again in 1405. The Augustinian Priory of St John the Evangelist and St Teulyddog stood by the river, and in the priory's scriptorium, around 1250, scribes copied out the Black Book. The plague came up the Towy with the river trade in 1347, and a mass grave was dug behind what is now St Catherine Street. In 1456 Edmund Tudor, Earl of Richmond, caught plague here and died, three months before the birth of his son. The boy would become Henry VII. Edmund was buried in the choir of the Grey Friars church on Lammas Street; his tomb was moved to St Davids Cathedral at the Dissolution, where it remains.
On a March day in 1555, in the marketplace at the centre of town, Bishop Robert Ferrar of St Davids was tied to a stake and burned alive. He was a Protestant during the brief reign of Mary I, and he would not recant. A small plaque set below the later statue of General Nott in what is now Nott Square marks the place where he died. John Foxe recorded his death in the Book of Martyrs. The town also hosted, in the centuries that followed, the Court of Great Sessions for southwest Wales, the largest population of any Welsh town for two hundred years, and one of the earliest recorded Eisteddfodau around 1451. Carmarthen was the chief city of the region until the coal valleys to the east overtook it in the 19th century, and the architecture downtown still reads as a county town that once thought it would be a capital.
In 1840, William Spurrell set up a printing press in Carmarthen. Over the next decade he compiled the first comprehensive Welsh-English dictionary, published in 1848, and an English-Welsh companion in 1850. Today's Collins Welsh dictionary is still informally known as the 'Collins Spurrell.' The town gave the printing press, the dictionary, the early Eisteddfod, the Black Book, and one of the earliest collections of police mugshots in Britain (the Carmarthen jail's 'Felons' Register' of 1843 to 1871). It also gave Plaid Cymru its first MP: in a 1966 by-election Gwynfor Evans took the Carmarthen seat, the first Welsh nationalist ever elected to Westminster. The town tends to be remembered for the things it lost - the oak, the castle, the friary, the elephant a travelling circus buried under the rugby pitch - but the list of what it kept is longer.
Stand on Castle Hill, where the gatehouse and motte are still visible behind the early 20th-century County Hall designed by Sir Percy Thomas, and you can see most of the town in a single glance: the long nave of St Peter's church, the largest in the diocese; Clough Williams-Ellis's 1937 concrete bridge over the Towy; the cable-stayed pedestrian span that connects the railway station to Blue Street; the close-built streets running back from the river. The cattle market is a cinema and a shopping centre now. The Welsh language is still alive on the street and in the schools, and the town's Welsh name has, since the 2024 boundary review, become its primary parliamentary name: Caerfyrddin. Merlin's fort. The oak is gone, but the town it protected is not.
Carmarthen sits at roughly 51.86°N, 4.31°W on the River Towy, about 8 miles inland from Carmarthen Bay in southwest Wales. The town fills the inside of a bend in the river; from the air, the most obvious landmarks are Castle Hill on the north bank with County Hall on top of it, the long stretch of the A48 dual carriageway running west out of town, and the broad muddy estuary opening to the south. The wooded ridge of Merlin's Hill rises just to the east at Abergwili. Nearest civil airfields are Pembrey (EGFP) about 12 nm south on Carmarthen Bay, Swansea (EGFH) about 25 nm east-southeast, and Haverfordwest (EGFE) about 25 nm west. The Towy valley is a clear visual line running northeast inland from the bay.