In 1283 King Edward I of England began building Caernarvon Castle.
As he prepared to establish English government in Wales, Edward wanted to make a triumphalist expression of his imperial ambitions at Caernarvon.
He chose Caernarvon because the town was an ancient stronghold for the princes of Gwynedd.
King Edward also chose Caernarvon because of the town's strategic position overlooking the Menai Straits.
Caernarvon Castle has polygonal rather than circular drum towers.
The castle has cross-banded masonry (alternate strips of light and dark stone) in the defensive walls.
The polygonal towers and cross-banded walls were a homage to the Theodosian Wall at Constantinople.
King Edward I and his chief architect, Master James of St. Georges, had seen the Theodosian Wall while on Crusade.
At the western end of Caernarvon Castle stands the Eagle Tower.
At 124 feet The Eagle Tower was one of the tallest single towers erected in the Middle Ages.
When first built, the Eagle Tower had a stone eagel on each of its three turrets.