How to Build a Castle

A talk by Tim Lloyd on Saturday 10th December 2023

Experimental archaeology conjures images of painstaking research into ancient craft techniques or the reconstruction of buildings, such as round houses, from the results of excavations. At Guedelon, in France, a dedicated team have gone far beyond this by working for 25 years to construct a complete medieval castle from scratch.

Chateau de Chenonceaux

The strapline in French is “Nous batissons un chateau-fort” – “we are building a strong chateau”. The term “chateau-fort” is worth exploring as this sheds light on the origins of the project. English tourists know that a “chateau” is a renaissance confection fulfilling the role of what in England would be called a “Stately Home” (usually in the care of the National Trust). A “castle”, as every schoolchild knows, is a large, partially ruined fortification like the many constructed from the Normans to the Tudors to express power and hold land. These also exist in France so to make the distinction they are called a “chateau-fort”.

Louvre – basement foundations of the medieval castle


The distinction is complicated by the fact that many chateaux are domesticated adaptations of earlier fortified structures. A famous example is the Louvre in Paris. Now a museum, recently a palace but underneath it lies a medieval castle. In fact, it is possible to tour the basement and see the foundations of this once impressive fortress. So, when Michel Guyot bought Chateau Saint-Fargeau in western Burgundy he immediately commissioned a team of experts to investigate its origins.

Chateau Sant-Fargeau

Sure enough, it was discovered that the chateau was indeed once a medieval castle. Monsieur Guyot, who was already practised at restoring old historic buildings, had an initial idea to return the building to its earlier form. Realising the enormity of that task, he then decided it would be almost easier, and certainly more interesting, to build a new castle from scratch. And so he raised some initial finance, commissioned the same experts and set about the project that was to become Guédelon.

Saint Fargeau – the castle beneath


It was decided to design a castle based on the architectural canons laid down by Philip Augustus in the 12th and 13th centuries. This was a turbulent period in French history as the Capetian kings fought to wrest control of the west of the country from the Plantagenet and Angevin kings of England.

Philip II Augustus, King of France from 1180-1223, is attributed with standardising the military architecture of castles in the French kingdom. Examples of this standard plan include the Louvre in Paris, and Dourdan Yévre-le-Châtel castle in Loiret, or more locally, the castles of Ratilly or Druyes-les-Belles-Fontaines in Yonne. 

Dourdan Chateau-fort

Castles built to this standard plan have the following characteristics: a polygonal ground plan; high stone curtain walls, often built on battered (sloping) plinths; a dry ditch; round flanking towers pierced with single embrasured arrow loops, the position of which is staggered on each floor of the tower; one corner tower, higher and larger than the rest: the tour maîtresse; twin drum towers protect the gate. Much of this was intended to facilitate the rapid construction of castles to a restricted budget.

A back-story was created to underpin the project. The start of the construction was taken as being 1228 (770 years from the actual start in 1998). The fictional builder of Guédelon castle is Guilbert, a low-ranking local lord, vassal of Jean de Toucy, himself vassal to the king of France. The lord of Guédelon has married Jean de Toucy’s niece and so married into a powerful local family. His wife’s dowry brings him land, mills and woodlands over which he can exercise seigneurial rights. His overlord has just granted him “licence to crenellate”. 

Initial design for Guédelon


A site was found at a disused quarry in the wood of Guedelon. Located in the department of Puisaye it is only a few miles from Fargeau and about 2 hours south of Paris.Plans were drawn up and planning permission was granted on July 25th 1997. A formidable local company CEO, Maryline Martin, was appointed to head the project. She is still CEO of the successful enterprise to this day. Once the project was able to receive visitors it has generated enough income to sustain construction ever since.

The site being cleared in 1998


The aim was to recreate the site organisation and construction processes that might have existed on an early 13th-century building site. Right from the start, a scientific advisory committee made up of archaeologists, historians and castellologists has been associated with this unconventional project. Certain experts join “en route” according to the needs and progress of the project or their research. A lot of information was gleaned from medieval illustrations but there was still much experimentation to be done.

A medieval building site

There are no modern tools used on site let alone any with power. Metal tools are made in the on-site forge and measuring implements are based on ancient wooden examples. A favourite feature is the large treadmill crane used to haul materials up to the top of the construction.

The treadmill crane in action

Although the workers all dress in medieval garb, an important exception has been to ensure health and safety by mandating safety shoes and, where necessary, hard hats (disguised by coverings of hessian). Scaffolding has to be constructed to modern standards and, although rope is made on site, only industrial standard rope is used to raise heavy loads.

Safety boots and hat

Materials and Methods

Building in a quarry in a wood means that there is no shortage of stone and wood. The hard local sandstone is quarried to supply stone of varying precision according to the needs – from fully dressed blocks to rubble cores.

The sandstone quarry

Finer elements, such as vaults and windows, are carved from limestone imported from a nearby quarry. These are worked on by a team of male and female masons working in the typical masons’ lodge just outside the curtain wall. All the materials are carried around the site by hand or on a cart pulled by one of a team of heavy horses.

Stonemason at work in the lodge

Limestone is also imported to be burnt in ovens to make quick-lime. This is mixed by hand with sand to provide the mortar that holds the stonework together.

Carpentry is all done using historic tools so there is no sawmill or machine cutting. Wood is vital, not only for the construction of roof timbers and doors, but for the supporting elements of arches and vaults. The curtain walls all betray evidence of “putlogs” – holes left by the attachment of wooden scaffolding as the structure grows in height.

A tower roof

There is plenty of usable clay in the wood so a formidable workshop creates tiles for rooves and floors as well as vessels for the workers’ use. These were originally fired in temporary clamp kilns but there is now a large permanent kiln.

Roof tiles

The afore-mentioned forge is part of a large blacksmiths shop making all the ironwork required on site. They have even experimented with smelting iron from ore. The story of this, and other aspects of the project, is told in a fascinating YouTube series called “Les Feux du Guédelon”.

Blacksmith making chisels for stone-working

Many other crafts are represented, from weaving and dying to basketry and gardening. All can be viewed in progress by visitors to the site. The project has only about 40 permanent staff but this is swelled in season by trainees who visit to learn about historic construction. In fact, the project has contributed expertise to the restoration of the Notre Dame de Paris.

The Castle in 2023

When Tim first visited in 2015 the walls were less than half height but the Great Hall (Logis de Seigneur) was built and the two adjoining towers were well under way. At his second visit in 2023, he found that the chapel tower was complete and the Great Tower and SW “Dovecote” Tower were only lacking rooves. This latter was completed at the end of the season. Meanwhile the twin towers of the gatehouse are under intensive construction and will probably be completed in 2024.

At the end of the 2022 season

The towers all contain vaulted ceilings, a major learning curve for the team. The rooves are all conical with coverings of tiles. This is typical of French castles and their descendant chateaux. It is not clear if this was ever the fashion in England.

Great Hall

Internally, the rooms have been finished according to the standard that the fictional Guilbert could probably afford. The chapel is lovingly plastered and painted with simple star and flower motifs. The walls of the great hall are left in natural dressed stone but the solar (lord’s sitting room) next to it is plastered and painted with formal designs inspired by a nearby church that has frescos from the period. Windows do not contain expensive glass but, in the hall and chapel, are fitted with wooden frames across which translucent silk has been stretched and painted.

The solar

The ground floor of the hall is taken up by a kitchen and enormous store room.

Baking bread from flour ground in the castle mill

The Great Tower is in effect the keep, or stronghold of last resort. It contains a large, vaulted room which is the lord’s chamber. Above and below this are other rooms. All the towers have several rooms including the SW tower which has a dovecote in the top level.

Lord’s chamber in the Great Tower

Visiting Guédelon

Guédelon is located between the main tourist areas of Burgundy and the Loire but is a feasible day trip from either. It is even accessible from Paris and coach excursions run from the capital in high season. It is open from the end of March to the beginning of November, apart from a couple of special days. Entrance is reasonably priced and it is worth allocating a whole day.

Location map

There is a shop, toilets, snack bar and a large café. A good tip is NOT to eat your lunch from 12:30 to 2pm, despite the fact that all the workers will be on lunch break, as all  the visitors (especially the French) will be eating at this time.

Lots to see!

For more information see

Note: the images in this report are from various sources and may be subject to copyright

Exploring the archaeology, history and heritage of Berkshire