The name is alleged to derive from the word for a ford, river-crossing or river (see Guad- and Guadal-). In local myths there was a 6th-century king Hoël (possible link to King Coel) known as the forest king or "Rex Arboretanus". It is a fact that the town is situated amidst the vast forests of Poutrecouët. A royal castle from this era was sited at Meu, not far from Gaël. This later became the seat of the De Montfort family. The emplacement was captured and dismantled by De Guesclin in 1372.