Secrets of the Castle: with Ruth, Peter and Tom Historian Ruth Goodman and archaeologists Peter Ginn and Tom Pinfold turn the clock back as they learn how to build a medieval castle using the same tools, techniques and materials available in the 13th century. Although Britain has some of the finest remaining castles of the medieval period, many of their secrets have been lost in time.

Part 1
Historian Ruth Goodman and archaeologists Peter Ginn and Tom Pinfold learn the skills of medieval castle builders by heading to Guedelon in the Burgundy region of France. They spend six months working on the world's largest archaeological experiment - a 25-year project to build a medieval castle from scratch, using only the tools and materials available in the 13th century. In the first episode, Peter and Tom are taught the skills of medieval stonemasons as they help construct a spiral staircase, while Ruth sets about equipping the simple wattle and daub hovel that is to be their base.
Part 2
Historian Ruth Goodman and archaeologists Tom Pinfold and Peter Ginn explore the art of medieval combat and the construction of a castle's defensive structures. They look at the ingenious features 13th-century builders came up with to withstand attack from a formidable array of siege engines, and explore the craft behind the weapons they had to resist, from trebuchets to crossbows. Ruth has a go at making cloth armour in the form of a gambeson, while Tom and Peter get to grips with constructing arrow loops, a key defensive feature of the castle walls.
Part 3
This edition focuses on the surprisingly colourful world of medieval interior design, with Peter Ginn and Tom Pinfold rendering and lime-washing the inside walls of a guard tower, transforming its dark stone walls into a bright space. Ruth Goodman makes paint and decorates the castle bedchamber using designs based on those recently discovered at an 11th-century church nearby, and Peter gets to grips with the indoor toilets known as garderobes.
Part 4
Ruth Goodman, Peter Ginn and Tom Pinfold examine the ways in which every aspect of the construction of a castle required the stonemasons, blacksmiths and carpenters to co-ordinate their efforts - from making and sharpening tools, to processing wood, and securing timber scaffolding on the castle walls. Peter and Tom help fix the Guedelon water mill, which is having major teething problems, and the team follows the progress of the construction of a wooden walkway connecting the chapel tower with the Great Hall.
Part 5
As their time in Burgundy draws to an end, the team looks at the castle's place in the wider medieval world. Peter Ginn visits nearby Vezelay Abbey to examine the influences that were shaping the stone architecture of the period, and back at Guedelon he helps build an ornate entrance to the chapel inspired by ideas from distant lands. Ruth Goodman explores how pilgrimage was a means by which anyone - regardless of class, age or gender - could travel to far-off places, while Tom Pinfold works on a new door for the kitchen. The three come together to help with one of the castle's most ambitious projects to date, a spectacular limestone window for the chapel