Llywelyn ab Iorwerth (Llywelyn Fawr) commissioned the construction of Dolbadarn Castle some time before 1230. The castle is strategically positioned on a mount above Llyn Padarn in Llanberis, and from this position, it was possible to defend Snowdonia from any threats that came from the direction of the Llanberis Pass. The road through the Llanberis Pass was a main route through Wales, and therefore, Dolbadarn Castle enabled the Princes to rule and monitor movements through north Wales.
Dolbadarn Castle (© Crown copyright (2014) Visit Wales)
Llywelyn Fawr’s castles re-enforced Snowdonia’s natural defences: its mountainous terrain, forests and rivers, but since the castles were fairly small, it is more likely that the real aim was to re-enforce the Princes of Gwynedd’s power within the principality itself.
Following the death of Dafydd ap Llywelyn, Llywelyn Fawr’s heir, in 1246, his nephews, Owain Goch, Llywelyn ap Gruffudd and Dafydd ap Gruffudd, fought for supremacy in Gwynedd. They were the sons of Dafydd’s brother, Gruffudd ap Llywelyn, who was imprisoned in the Tower of London. The three brothers fought a battle in Bwlch Derwin, Eifionydd, where Llywelyn ap Gruffudd was victorious and Owain Goch was imprisoned in the tower of Dolbadarn Castle for over twenty years, from 1255 to 1277. According to Brut y Tywysogion, Dafydd escaped from the area following the Battle of Bwlch Derwin, although evidence suggests that he held Dolbadarn Castle during the wars between Llywelyn ap Gruffudd and Edward I.
Llywelyn ap Gruffudd was killed at Cilmeri in 1282 and following this, Dafydd made one last attempt for independence from English rule. Dolbadarn Castle was Dafydd ap Llywelyn’s last stronghold in Snowdonia: he held his last courts there at the end of May 1283 and he also signed his last documents there, but by June 21st, 1283, his fellow Welshmen had handed him over to Edward I, and he was viciously executed in Shrewsbury.
Once he had conquered Gwynedd, Edward I had very little interest in Dolbadarn Castle and decided to focus on developing his own castle in Caernarfon instead. Beams and various other features were carried from Dolbadarn Castle, and used in Caernarfon Castle.
In the context of early C13 military architecture, Dolbadarn Castle is highly sophisticated and the castle’s tower is perceived to be the best surviving example of a Welsh round tower. Another two towers are located on the site, but these were never very high and the castle walls measure a depth of eight feet.
Very little evidence survives of activity at Dolbadarn Castle after the early C14, but it is suggested that Owain Glyndŵr held his captives there circa the year 1400. Since then, Dolbadarn Castle has become widely associated with artists of the Romantic Period, such as J.M.W.Turner.