A series of eerie symbols and markings have been discovered under the floorboards of one of Britain’s most important historic houses, scratched into the wood to protect King James I from witches.

The so-called witchmarks were found under the floorboards in a bedroom at Knole, the huge stately home in Kent, during an archaeological survey. They were dated to the early 17th century, when hysteria over witchcraft had reached fever pitch.

Nathalie Cohen, an archaeologist at the National Trust, said the discovery was “a complete surprise”, adding: “It gives us an insight into the minds of the people who lived and worked at Knole and their belief systems.”

According to experts the ritual protection marks, which were found across the property, illustrate “how fear governed the everyday lives of people living through the tumultuous years of the early 17th century”.

Witchmarks, also known as apotropaic marks, have been found in parish churches and domestic buildings across the country from the time, placed there to ward off evil.

King James I ruled England from 1603 (Getty) (Getty Images)

The symbols found in the Upper King’s Room at Knole are each about the size of a fist and were arranged around the chimney as a “demon trap”.

“In the 17th century they believed witches and demons could come through open doors, windows or down the fireplace. You can’t shut the chimney off so they created a virtual protective box,” Ms Cohen said.

Some of the marks are mesh designs and others are symbols including one invoking the protection of the Virgin Mary. The markings were described as “a bit Blair Witch-y” in reference to symbols seen in the 1999 horror film.

A team of archaeologists discovered the patterns scratched into the wooden beams and joists below the floorboards earlier this year. Using tree-ring dating, they estimated that the witchmarks were made in early 1606.

Craftsmen working for Knole’s owner Thomas Sackville are believed to have carved the marks ahead of a proposed visit by King James I and just months after the Gunpowder Plot had been foiled.

The plot had caused mass hysteria to sweep the country and accusations of demonic forces and witchcraft were rife.

English conspirator Guy Fawkes is interrogated by King James I after his arrest for planning to blow up the House of Lords (Getty) (Getty Images)

James Wright, buildings archaeologist at Museum of London Archaeology, said the King had a “keen interest in witchcraft and passed a witchcraft law, making it an offence punishable by death and even wrote a book on the topic entitled Daemonologie”.

Sackville, who was Lord Treasurer, created a royal suite to attract the King, but he then died and James never visited.

The National Trust is currently carrying conservation and restoration work at Knole, and it was during this process that the marks were discovered. Many of the floorboards had never been lifted before, and other artifacts and textiles were also found.

It has a collection of royal furniture, silver, paintings and tapestries and has a history stretching back 600 years and was the setting for Virginia Woolf’s novel Orlando.