Vortiporius

thumb|170px|right|Map showing Dyfed, after the late 7th century, showing its seven cantrefi. thumb|170px|right|Map showing the location of Dyfed in southwesternmost Wales. Vortiporius, often shortened to Vortipor (, or Gwerthefyr), was a king of Dyfed in the early to mid-6th century. He ruled over an area approximately corresponding to modern Pembrokeshire, and Carmarthenshire, Wales. Records from this era are scant, and virtually nothing is known of him or his kingdom. The only contemporary information about Vortiporius comes from the Welsh ecclesiastic Gildas, in a highly allegorical condemnation from his De Excidio et Conquestu Britanniae (). At the time the work was written (c. 540), Gildas says that Vortiporius was king of Dyfed, that he was grey with age, that his wife had died, and that he had at least one daughter.

As a legendary king in Geoffrey of Monmouth's 12th-century treatment of the Matter of Britain, the Historia Regum Britanniae, Vortiporius was the successor of Aurelius Conanus and was succeeded by Malgo. He is not mentioned in the 9th-century Historia Brittonum attributed to Nennius. Vortiporius appears in the Irish genealogy given in the 8th-century work The Expulsion of the Déisi, in which his name is given as Gartbuir. The pedigree given in the Harley MS 5389, written c. 1100, is nearly identical, with his name given as Guortepir. In the Jesus College MS. 20, he is called Gwrdeber. The genealogy in Expulsion says he was a descendant of Eochaid Allmuir ( [literally (from) Overseas]), who is said to have led a sept of the Déisi in their settlement of Dyfed c. 270.