Three letters dating back to the seventeenth century have been discovered under the floorboards at a Sevenoaks attraction.

The rare find included two pieces of correspondence, dated May 1603 and October 1633, in an attic at Knole House's South Barracks, and a third, from February 1622, among the debris in a ceiling void by the Upper King’s Room.

The exciting discovery was made by volunteer Jim Parker as work began on opening up more of the historic house's spaces to the public, a five-year project supported by the Heritage Lottery Fund.

Mr Parker said: "I was very excited to see some pieces of paper hidden underneath some rush matting. The first piece was folded and very dusty. We realised it was a letter and there was writing on it which looked like a seventeenth century hand. I was nicknamed ‘Jimdiana Jones’ after that!"

On the day the letters were discovered, the team was sifting through the dusty voids in the attic of the South Barracks. Their only finds had been a few old nails and some small animal bones, probably the remnants of a long-forgotten meal.

All three letters were written on rag paper, a high quality parchment popular during the seventeenth century.

The 1633 letter is an appeal for domestic items to be sent to Copt Hall in Essex from a house in London, giving an intriguing insight into life in a country house 400 years ago. It is well written, suggesting it was compiled by a distinguished servant.

Records at Knole show that many large items, including trunks of linen and furniture, were moved from Copt Hall to Knole around this time. Trunks filled with papers were stored in the attic after the move, explaining how some may have slipped beneath the floorboards.

The connection between Knole and Copt Hall came about by the marriage between Frances Cranfield, daughter of the Earl of Middlesex who owned Copt Hall, to Richard Sackville the 5 Earl of Dorset and owner of Knole in 1637.

The collection at Copt Hall was moved to Knole during the early eighteenth century and forms a substantial part of collection now in the showrooms.

The 1622 letter seems to be a thank you note to a kind benefactor.

This is the first time such a discovery has been made at Knole.

Jan Cutajar, objects conservator, said: "The biggest challenge was the significance of the letters. I was conscious the work had to be of the highest quality. When you think that you’re reading someone’s handwriting from 400 years ago, it sends chills down your spine."

The letters have now been cleaned and put on display in the Visitor Centre.