IDA tweeted: “Our carbon dating testing yielded surprise results!
“More work is required by it appears that Althorp may have been occupied far longer than previously thought.
“It has a complex site with many interesting secrets!”
Althorp Estate is the family home of Earl and Countess Spencer and covers some 13,000 acres of beautiful land in West Northamptonshire.
At the heart of the estate is Althorp House where Princess Diana lived as a child.
After she died in 1997, she was buried on the estate’s grounds on a small island on a lake known as The Oval within the estate’s Pleasure Garden.