Dolbadarn Castle is a fortification built by the Welsh prince Llywellyn ap Iorwerth, Llywellyn the Great during the early 13th century. The castle was important both militarily and as a symbol of Llywellyn's power and authority. Situated at the entrance to Llanberis Pass it protected the old village of Llanberis located where Nant Peris is now. The castle features a large stone keep which is considered to be the finest surviving example of a Welsh round tower. In 1284 Dolbadarn was taken by King Edward I who built a new castle at Caernarfon. The castle was used as a manor house for some years, before falling into ruin. In the 18th and 19th century it was a popular destination for painters, Turners painting is considered to be iconic .
It is now owned by CADW the Welsh Government's historic environment service. Cadw means 'to keep' or 'to protect' in Welsh.