History of Caernarfon Castle

From Roman fort to royal birthplace to UNESCO World Heritage Site — the events and people behind 700 years of history.

700 years of history

Timeline

AD 77–78

Segontium Roman Fort

A Roman fort named Segontium stood half a mile from the current castle — the likely source of the town's Welsh name, "Caer yn Arfon" ("the fort in Arfon").

1283

Construction begins

Fresh from defeating the last native Welsh princes, Edward I orders Caernarfon's construction and puts Master James of St George in charge of the design, alongside new town walls and a quay.

25 April 1284

Birth of Edward II

Queen Eleanor of Castile gives birth to the future Edward II at Caernarfon — the king who, in 1301, becomes the first English Prince of Wales.

1294–95

Madog ap Llywelyn's revolt

Welsh forces under Madog ap Llywelyn sack the unfinished castle and town. Edward I has it recaptured and orders the defenses strengthened.

1330

Building work winds down

After roughly 47 years and around £25,000 spent, work on the castle effectively stops. Much of the planned interior, including the Great Hall, is never finished.

1403–04

Owain Glyndŵr's revolt

Owain Glyndŵr's forces besiege Caernarfon during the Welsh War of Independence. A small English garrison holds the castle.

1642–46

English Civil War

Held for the Royalist cause, Caernarfon Castle sees its last military action before surrendering to Parliamentary forces in 1646.

13 July 1911

Investiture of Edward, Prince of Wales

David Lloyd George, then Constable of the castle, helps stage the investiture of the future Edward VIII in the restored outer bailey — the first such ceremony held at Caernarfon.

1 July 1969

Investiture of Charles, Prince of Wales

The future King Charles III is invested as Prince of Wales at Caernarfon in a televised ceremony watched by an international audience.

1986

UNESCO World Heritage Site

Caernarfon is inscribed as part of the "Castles and Town Walls of King Edward in Gwynedd" UNESCO World Heritage Site, alongside Conwy, Beaumaris and Harlech.

Who shaped the castle

Key Figures

Edward I

King of England who ordered Caernarfon built after conquering Gwynedd, intending it as the symbolic seat of his new rule over Wales.

Master James of St George

Edward I's master architect and master of the king's works in Wales, responsible for the castle's design and several of Edward's other Welsh castles.

Eleanor of Castile

Edward I's queen, who gave birth to the future Edward II at the castle in 1284, while it was still a construction site.

Owain Glyndŵr

Welsh nobleman who led the early-15th-century revolt against English rule, besieging Caernarfon during his campaign.

David Lloyd George

Constable of Caernarfon Castle and British Prime Minister, who helped organise the 1911 investiture ceremony held at the castle.

King Charles III

Invested as Prince of Wales at Caernarfon in 1969, in a ceremony broadcast to a global television audience.

Several Caernarfon Castle guided tours spend significant time on this history — the small-group tour from Holyhead, in particular, stops at the room traditionally linked to Edward II's birth and the outer bailey investiture site. For the building's physical layout, see Caernarfon Castle's architecture and layout.

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