Battle Castle: Conwy 360 from Battle Castle on Vimeo.

The Story

Location: Wales


The build: Conwy was built by King Edward I of England in the late 13th century in Snowdonia, northern Wales. Part of the famous “Iron Ring” of fortifications, it was designed by Edward’s top military architect, Master James of St. George, to suppress Welsh rebellions against English rule.

A striking example of Edward’s distinct vision, this fortification is strategically positioned on the River Conwy. Its deadly entrance, lofty crenellated towers, and cleverly-designed river gate are statements to its determined King and enduring domination.

The siege: This stronghold was attacked by the Madog ap Llywelyn after he launched a campaign against the English in 1294. The leader, calling himself Prince of Wales, was armed with the powerful longbow. His army targeted several castles including Harlech – which was besieged – and Caernarfon – where the town and castle were sacked. Edward was present in the castle during the siege of Conwy and the outcome of the uprising would not only decide the destiny of England’s holdings in Wales – it would also inspire the King to attempt to perfect castle engineering by raising the mighty Beaumaris.

Castle Facts


  • A major feature of Edward’s Welsh castles is direct access to shipping channels. Harlech, Caernarfon, Conwy, and Beaumaris were all built close to the shore. This was known as the ‘way from the sea’.
  • Madog ap Llywelyn, leader of the 1294-95 Welsh rebellion, was actually in the pay of Edward I – the English king who he rallied against – in 1277.
  • Edward I built no less than eight major castles in Wales during his reign, some with substantial towns attached.
  • Conwy’s town was actually built on the very site where the ancestors of Llywelyn ap Gruffudd, the last prince of independent Wales, were buried. With 21 towers and three gatehouses, it is the largest of its kind.
  • The combined costs of Edward I’s 1282-83 Welsh military campaign and the castle-building program that followed was equivalent to more than $157,000,000 CAD in modern dollars.
  • None of Edward I’s castles were completed in less than five building seasons – which were six to seven months each – and three of them took much longer.


  • Several of Edward’s Welsh castles are known for their incredible gatehouses. These represent the peak of development in this area, and turn a necessary weakness – a hole in the wall – into the most heavily-guarded part of the castle.
  • Edward I was advised that integrating the Welsh into his newly-built towns would be the quickest way to ‘civilize’ them, but the English did the exact opposite – officially, Welshmen were excluded from these settlements.
  • The Welsh castle-building programs at Caernarfon and Beaumaris – along with the painting of the king’s chambers in Westminster – were the only exceptions to a freeze on royal works during the Scottish wars, when the Crown needed money.
  • When Edward I marched into Wales in 1294, he brought with him an army four times bigger than the one that had successfully conquered the country more than a decade before.
  • In 1283-84, about 4,000 men were employed to construct Conwy, Caernarfon, and Harlech. In total, this castle-building program may have absorbed up to a tenth of England’s workforce.

Featured Structure

Created with Admarket’s flickrSLiDR.

The arrow slit (or arrow loop) first appears in historical accounts describing the siege of Syracuse in the 2nd century B.C. Integrated into a castle’s design, they are engineered so archers can fire at the enemy under protection of a wall or merlon. Though these defensive features were seen in Greek and Roman fortifications, they does not seem to have been built into medieval European castles until the late 12th century. But they caught on fast. By the 13th century, arrow slits were standard issue for most fortifications.

Not surprisingly, Edward’s Welsh castles incorporated this military engineering ubiquitously. At Harlech, guardrooms at the ground floor on either side of the gatehouse boast these deadly features. Conwy’s arrow slits are lined with distinct red sandstone, which is harder than the dark blue grey sandstone used to build most of the castle and therefore better suited for this type of key structural stonework. And at Caernarfon, arrow slits are uniquely arranged to exploit the power of archery in a lethal way. At Conwy and Caernarfon, merlons are also slotted so that garrisons could fire from above without being exposed. The town walls were also equipped with arrow slits – the roofless, open-backed towers that line these defences were designed to guard English settlements in the wilds of Wales.

Motion Comic

Conwy Castle’s motion comic reveals the bloody history of Edward I’s relationship with his neighbours the Welsh which resulted in the construction and sieging of his great Iron Ring of Castles in Snowdonia, North Wales. The castle’s build, as well as this siege, are profiled in Battle Castle Episode 4: Conwy Castle. This comic contains stylized violence.

History Makers