This stone is believed to be a memorial to Vortipor, King of Demetia (modern Dyfed), who lived approximately AD475-540.
The stone pillar is just over two metres high.
On one face there is a Latin inscription, with an Ogham inscription along the left and top edge. The cross indicates that Vortipor was a Christian.
It is thought that Voteporigis or Votecorigas in the Latin and Ogham inscriptions is Vortipor, but some scholars claim the lack of an R in the first syllable of the name cannot be reconciled with the spelling given in historical sources.
The Romans brought Irish mercenaries across in the late 4th Century for protection from attacks by other Hibernians.
After the Romans left, the Irish Deisi (or Déssi) tribe of the County Waterford area ruled the region, hence the Ogham inscription as well as Latin.
They initially used the Roman title of 'Protector' (protictoris) instead of the British equivalent of King.
The site of the memorial stone may reflect a continuation of the Roman custom of roadside burial, or may simply have been intended to let the memorial be seen by people travelling along the road. The Roman road replaced an old track, and it is possible that the stone was originally one of a pair of boundary markers that straddled the track in the Stone Age, which was reused for Vortipor’s memorial.
The stone stood near a stile on the south side of the Castell Dwyran churchyard until it was removed during repairs to the fence in 1879. The stone's location at the church was next to a meadow known locally as Parc y Eglwys. Local tradition warns that the land near the church must not be ploughed, else there would be “thunderings and lightings and the cattle will die”. The meadow had evidence of large hut-circles, and is only 200 metres off the line of the Roman Road.
In 1921 the stone was given to Carmarthen Museum.