Caermarthen is one of three castles built in the Island of Britain at the request of Helen Luyddawc, and a place connected both to Maxen Wledig’s imperial presence and to the roads Helen had made across the island. Its account joins a chosen site and a royal building program to place-names said to endure beyond the events themselves.

Foundation and Royal Selection

After Maxen Wledig married Helen, she asked for the Island of Britain, from the Channel to the Irish Sea, together with three adjacent islands, to be held for her father under the Empress of Rome. She also requested three chief castles at locations of her choosing. The highest was to stand at Arvon; the other two were Caerlleon and Caermarthen. Earth was brought from Rome to the castle at Arvon so that Maxen could sleep, sit, and walk on ground thought more healthful to him. Caermarthen thus belonged to a wider scheme of authority and construction, though the account does not assign it the distinction given to Arvon.

Maxen’s Visit and the Name Caervyrddin

Maxen later went hunting at Caermarthen and travelled as far as the summit of Brevi Vawr, where he pitched his tent. The place of his encampment was called Cadeir Maxen, a name the narrative says remained in use. The account also says that Caervyrddin was built with a myriad of men and gives that name to the castle. Caermarthen and Caervyrddin are therefore linked in the narrative’s naming of the site and its construction, while the hunting journey supplies a separate place-name associated with Maxen’s stay.

Helen’s Roads and the Wider Setting

Helen arranged for high roads to be made between one castle and another throughout the Island of Britain. They were called the roads of Helen Luyddawc because she was descended from a native of the island; the account adds that the island’s people would not have built such great roads for anyone else. Caermarthen consequently appears not as an isolated fortress but as one point in Helen’s network of castles and routes. Maxen remained in the island for seven years, a span the narrative connects to a Roman custom: an emperor who stayed abroad longer than seven years risked losing his position and never returning to Rome.