The tomb became an enclosed vault after an 18th Century earl raised the roof.

Maidwell Hall in Northamptonshire said it was "sobering" to read about the earl's experiences.

The earl spoke to his friends and contemporaries, who he says had "locked" their memories away and found solace in sharing their stories with him.

The earl is loathe now to talk specifically about the pressures on his two nephews and the rift between them.

Some people suggested it belonged to a local earl.