The sixth in a series of caches around Mathern [Merthyr Tewdrig].
According to the Book of Llandaff, Tewdric (or Tewdrig), king of the Celtic kingdom of Morgannwg (Gwent and Glywysing) was wounded in a battle against the invading Saxons at Tintern
Tewdric was given the prophecy that he will be successful in battle but will be mortally wounded; that a vehicle pulled by two stags, yoked, will appear and carry him towards his destination of Ynys Echni (Flatholm Island,) but that he will die in peace three days after the battle. Wherever the stags halted, fountains would gush forth but as they approached The Severn the wagon was broken, a very clear stream gushed forth there they bathed his wounds but they could not prevent him from passing away. His son, Meurig, kept his promise to build a church at the spot where he died.
Now known as St Tewdrics Well it was restored by Monmouth District Council in 1977, it has a very plain stone wall around it and is surrounded by a small fence. The Well is said never to freeze so it was an important water supply for livestock in a harsh winter.