Caerphilly Castle, Wales: The Second Biggest Castle in Britain, Built in Less Than Three Years

The Welsh Flag

Caerphilly Castle is undoubtedly one of the mightiest fortresses in Wales - and perhaps one of the grandest Medieval buildings in Western Europe.

This formidable castle, surrounded by two huge lakes, is located in the centre of the town of Caerphilly (about 25minutes drive north of Cardiff).

The castle is particularly interesting as it was built at breakneck speed - the vast majority was built in just three years, between 1268 and 1271.

Even by modern standards, you’d be hard pressed to construct such a vast stone fortress in just three years. The fact that builders managed this more than 700 years ago makes Caerphilly quite remarkable.

Caerphilly is also an early example of the concentric castle design - a style of building which rendered castles virtually impregnable. It influenced the construction of some of the mightiest of all fortresses in Wales.


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Caerphilly Castle panorama A stunning panorama of Caerphilly Castle. All these pics are my own.

Exploring Caerphilly Castle Today

Oddly enough, the approach to Caerphilly Castle is rather unassuming. Rather than being built on a raised rocky platform, it’s hidden within a dip in a plain.

Only when you cross the first moat to the outer gatehouse does the size of the castle really become apparent.

This vast structure spreads over more than 30 acres, and is commonly cited to be the second largest castle in Britain (after Windsor Castle).

Caerphilly Castle Southern Gatehouse This is the Southern gatehouse of the castle, which is now locked. It would have provided an access route between the castle and the Medieval town.

At many points, you can clearly see that the Pennant sandstone walls of the castle are more than a foot thick.

Subsidence and landslide have resulted in gaping cracks, which gnaw through many of the castle towers. Most impressively, though, is the castle’s famed South Eastern Tower.

Optimistically dubbed ‘the Welsh Tower of Pisa’, this Medieval tower leans at 10 degrees to the vertical - most likely because of subsidence. The effect is extremely impressive - especially up close.

Caerphilly Castle angled tower Due to subsidence, the South Eastern tower has a tilt of more than 10 degrees - greater than the Tower of Pisa! And, if you're wondering, that is Jesus you can see - a temporary sculpture placed alongside the tower for effect.

That’s certainly not the only highlight, though. As you climb one of the towers of the main gatehouse, the castle spreads out below - spanning four more gatehouses, three mighty towers, two rings of curtain wall, and one impressive Great Hall.

Climbing the castle also grants a beautiful view of the Welsh hills which encircle this patch of flat land - and gives you a neat overview of the anglers fishing in the two huge moats.

Caerphilly Castle view from gatehouse This is the view from the top of the inner gatehouse. In the foreground, you can see the first moat; the other moat is behind the external gatehouse at the far wall.

The Creator of the Castle: ‘Red’ Gilbert de Clare

There are two personalities which shaped Caerphilly Castle. Of the two men, Red Gilbert de Clare was the more important - without him, the castle would never have come to fruition.

‘Red’ Gilbert - so called because he had firey red hair - was born in 1245, and was a young and ambitious member of the de Clare family. The de Clares were lords over much of Southern Wales from 1217 onwards.

In 1263, Red Gilbert took control of his family’s lands after the death of his father. The young man was eager to make his mark upon Wales, and had inherited his family’s acquisitive desire for land.

There was a cloud on the horizon, however. The de Clares were effectively English - ruling over Welsh lands and subjects. In Northern Wales, Welsh Prince Llewellyn ap Gruffud was running a successful campaign to reclaim Welsh lands for the Welsh people.

Atop Caerphilly Castle gatehouse A breezy photo of the modern Welsh flag fluttering on the roof of the gatehouse.

Prince Llewellyn was gradually approaching the de Clare’s lands, and the King of England (at that time at least) seemed wholly unbothered by the threat.

Red Gilbert decided to take the matter into his own hands, and build a vast castle to deter the advance of Prince Llewellyn - who was just miles from Red Gilbert’s lands.

Red Gilbert was swimming in a family fortune, so the vast structure of Caerphilly was commissioned and built at dizzying speed. The threat of a Welsh rebellion struck fear into de Clare’s heart (indeed, Prince Llewellyn attacked and burned some of the castle foundations in 1270).

After a phenomenally speedy building effort, the vast majority of the castle, still visible today, was finished by late 1271.

A Fortress of Unimaginable Proportions

I can’t over-exaggerate the ambition and drive of Red Gilbert. He was an aggressive young man who wanted to make his mark on the world.

The sheer scale and strength of Caerphilly Castle was unequalled within Western Europe. It was an aggressive, testosterone-fuelled project of incredible ambition.

Of course, elements of the castle were borrowed from other fortresses. Inspired by the infamous siege of Kenilworth Castle, Red Gilbert commissioned two vast lakes to surround the fortress.

Caerphilly Castle moat wall The lakes and moats around Caerphilly are shallow, but they needed to be robustly dammed to prevent attackers from draining them. This vast structure has subsided over time (note the vast cracks along the supports), but helped preserve the water surrounding the castle.

The lakes were intended to deter attackers, siege engines, and even archers. By all accounts, they were very successful - Caerphilly never succumbed to siege.

Part of the castle - the East Gatehouse - was also inspired by fortresses elsewhere. It’s a close copy of a similar structure in Tonbridge Castle.

However, these architectural influences pale in significance compared to the overarching original design of the castle.

Caerphilly is an early example of the impregnable concentric castle design - effectively a castle within the walls of another castle. It was a quite revolutionary evolution of Medieval architecture.

Caerphilly Castle concentric design It's hard to capture in a photo, but notice how the lower outer walls encircle the higher walls of an inner fortress. This what is meant by 'concentric castle' (or 'castle in a castle') design.

Caerphilly’s early concentric design certainly influenced Edward I’s ‘iron ring’ of castles in North Wales, which were built around thirty years later. This series of castles includes Beaumaris and Caernarfon, both of which are protected as UNESCO World Heritage sites, because of their phenomenal design.

An Impregnable Fortress - Which Was Hardly Ever Used

Ironically enough, by the time that Caerphilly Castle was finished, the threat of Welsh Prince Llewellyn was dramatically receding.

In 1277, King Edward I was tiring of the troublesome Welsh Prince and drove him out of his reconquered lands. Caerphilly was no longer on the frontier of political dispute.

Red Gilbert died in 1295, but the strength of the castle was never really called into question. Save for a couple of minor Welsh rebellions, mighty Caerphilly survived virtually unscathed.

One interesting chapter did occur, though, in the 1320s. As Red Gilbert only had daughters and no son, the castle floundered in limbo for some years, with no obvious heir.

Eventually, the husband of his oldest daughter (Eleanor) grabbed a hold of the castle. Hugh Despenser, by all accounts, was a greedy and despicable character - cruel and also irrepressibly acquisitive.

Caerphilly Castle Eastern gatehouse This is the famed - and extremely beautiful - Eastern Gatehouse. The photo higher on the page (with the Welsh flag) is taken from the top. The windows of the Great Hall are to the right.

Despenser got his grubby mitts on increasingly large swathes of Welsh land, and was hated by the people of Wales. In 1326, he also extended and aggrandised part of Caerphilly’s Great Hall - the only other chunk of Medieval construction ever to take place within the castle.

Happily though, this grim character got his come-uppance. In late 1326, he sided with the detested King Edward II, who was facing rebellion against his hapless rule of England.

The pair holed themselves up in Caerphilly, and subsequently tried to hide elsewhere in Wales from the approaching popular uprising against them, lead by Isabella of France. Both were captured - Despenser hung, drawn and quartered; and Edward forced to abdicate - and face a grisly death.

From that point, the castle fell into a state of gradual decline.

Visiting Caerphilly Castle and the town of Caerphilly

With the kindest possible intentions, the town of Caerphilly is nothing to get excited about. Oddly, considering the vast numbers of visitors, there’s very little infrastructure for tourists, save two lone cafes adjacent to the castle.

Caerphilly town, nestled behind the castle The town of Caerphilly surrounds the castle. Unfortunately there's not much for visitors to see or do.

You’d definitely be better visiting on a few hours’ trip from Cardiff. I’d suggest taking your own picnic on a sunny day, as one of the cafes doesn’t even serve sandwiches.

Visiting will only take half a day or so, so you could comfortably squeeze in a trip to adjacent Raglan Castle, or even Cardiff Castle, if you were so inclined.

The castle is managed by the Welsh heritage body, Cadw. They lavish care on the place, and have installed some atmospheric audiovisual exhibits - for example, a cracking projection of a fire in the Great Hall - which help to bring the castle alive.

I've explored lots more incredible castles in Wales if you'd like to continue reading.

A Timeline of Caerphilly Castle

1217: The lordship of the Welsh lands of Glamorgan fell to the de Clare family.

1263: ‘Red’ Gilbert de Clare assumes control of the family lands, aged 18.

11 April 1268: In response to the threat of Welsh Prince Llewellyn, work begins on Red Gilbert’s castle.

13 Oct 1270: After political aggravation, Welsh Prince Llewellyn attacks and burns the castle foundations.

1 Jun 1271: Building work recommences upon the castle.

Late 1271: Majority of the castle completed.

1294: Welsh uprising against English rule. Most of Caerphilly is burned, but the castle survives relatively unscathed.

1295: Red Gilbert dies, aged 52. No obvious heir to the castle.

1310s: Greedy Hugh Despenser, husband to Red Gilbert’s oldest daughter (Eleanor) gradually acquires the castle and family lands.

1326: Great Hall of the castle modernised by despised Hugh Despenser.

1326: Rebellion against the despised Despenser and weakened King of England, Edward II. The two hole themselves up in Caerphilly but were captured elsewhere in Wales - and brutally executed.

Late 1300s: Castle is unused and gradually begins to decline and disintegrate.

1428/9: Some repair work undertaken by Earl of Warwick.

1539: An observer records ‘ruinous walls’ of ‘wonderful thickness’.

1642: Construction of a Civil War battlement alongside the castle, although it’s debated if it was ever actually used.

1776: The ruinous castle passes into the hands of the Marquesses of Bute. An interest in the picturesque means visitors start coming to the castle.

1928-1939: Vast renovations undertaken by Fourth Marquess of Bute.

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