The Demetae were a Celtic group living during the Iron Age and Roman times. They lived in areas now known as Pembrokeshire and Carmarthenshire in south-west Wales. This tribe was the namesake of the medieval kingdom called Dyfed. The modern region and county named Dyfed, as well as a unique way of speaking Welsh called Dyfedeg, are also linked to the Demetae.
Etymology and relationship to Dyfed
The tribal name Demetae is believed to come from an ancient Celtic language word connected to the modern Welsh word defaid (sheep) and the old Brythonic word defod (wealth, property, or riches). This word is still found in the name of the area in West Wales where the tribe lived. After the Roman Empire, the kingdom of Dyfed (dametos in an earlier Celtic form) continued to use this name. Even after the Normans took control of Wales and introduced a system for dividing land into counties, the name Dyfed remained in use. In the 1800s, Thomas Morgan recorded that people in Pembrokeshire still called the area Dyfed.
This connection to sheep is supported by evidence that the Demetae people were known for raising large numbers of sheep and goats, which provided much of their wealth. In modern times, experts like William Baxter noted that the names Dyfed and Demetae likely meant "a place suitable for raising sheep," as the region has long been known for its sheep farming.
History
The Demetae are named in Ptolemy's Geographia, which places them to the west of the Silures. Ptolemy listed two of their towns: Moridunum, which is now known as Carmarthen, and Luentinum, which is believed to be the Dolaucothi Gold Mines near Pumsaint in Carmarthenshire. The Demetae are not discussed in Tacitus's writings about Roman military actions in Wales, which focus instead on the Silures and Ordovices.
Vortiporius, called the "tyrant of the Demetae," is one of the kings criticized by Gildas in his 6th-century writing De Excidio et Conquestu Britanniae. This likely refers to the small kingdom of Dyfed during the time after the Romans left Britain.