Long before hikers climbed Snowdon for pleasure, the mountains of Eryri were part of a battlefield. Princes ruled from strongholds in the hills. Armies marched through passes. Castles guarded valleys and controlled kingdoms. Today the mountains are peaceful, but scattered across the landscape are fortresses that tell the turbulent story of Wales — from the Welsh princes who defied conquest to Edward I's extraordinary Iron Ring that finally subdued them.
The castles of Eryri divide into two distinct stories. The Welsh castles — Dolbadarn above Llanberis, Dolwyddelan in the mountain interior, Castell y Bere in the south — were built by the princes of Gwynedd as strategic tools to defend their mountain kingdom. They are smaller and more practical than their English counterparts, but their settings are often extraordinary. The Edwardian castles — Caernarfon, Harlech, Conwy, Beaumaris — were built by Edward I following his conquest of Wales and represent one of the most ambitious military-architectural projects of medieval Europe.
The Castles at a Glance
| Caernarfon Castle | Edward I's greatest fortress — UNESCO World Heritage Site |
| Harlech Castle | Dramatic clifftop setting — inspired "Men of Harlech" |
| Conwy Castle | Town walls intact — one of Europe's finest medieval fortifications |
| Beaumaris Castle | Anglesey — architecturally perfect concentric fortress |
| Dolbadarn Castle | Welsh princes' castle above Llanberis |
| Dolwyddelan Castle | Remote mountain fortress — birthplace of Llywelyn the Great |
| Criccieth Castle | Sea views across Cardigan Bay |
| Castell y Bere | Lonely Welsh stronghold in southern Eryri |
The Iron Ring
Caernarfon, Conwy, Harlech and Beaumaris together form what historians call Edward I's Iron Ring — a chain of castles designed to encircle and permanently control the heartland of Welsh resistance. Together they formed a single strategic system, supplied by sea and linked by roads. The four castles and the associated town walls are jointly designated a UNESCO World Heritage Site.
The Welsh Castles
Dolbadarn above Llanberis is the most dramatic of the Welsh castles — its round tower overlooks the lake and the entrance to Llanberis Pass from a position that controlled access into the mountains. Dolwyddelan in the Lledr Valley is more austere, perched on a rocky knoll in mountain country that feels genuinely remote even today. Castell y Bere, the least-visited, sits in southern Eryri among landscapes that feel almost entirely unchanged since the Middle Ages.
Independently written — Snowdon.com