A collection of several previously unseen historical treasures and artwork from Michelangelo are to go on display later.
The Harley Foundation in Worksop, Nottinghamshire, is set to open up the Portland Collection to the public on Saturday at Welbeck Abbey.
The collection was acquired over centuries by the Cavendish family.
It also includes an earring King Charles I was wearing when he was beheaded in 1649.
The family has owned the Welbeck Estate since the 17th Century.
Lisa Dee, the director of the Harley Foundation, said: "In this exhibition, we've got the early Tudor and Jacobean portraits we haven't shown before - in fact, some that haven't been on public display ever."
Michelangelo's 1538 piece - Madonna del Silenzio - is also on display.
The red chalk picture forms one of just a handful of the famous Italian's artwork on show across the UK.
"It is an amazing thing because Worksop is only one of four locations in the whole of the UK which has a Michelangelo on public display," Ms Dee said.
The pearl earring worn by King Charles I at his execution, taken from his severed head, is also on show.
Ms Dee said her favourite piece was a portrait of the former Countess of Southampton, Rachel de Ruvigny, painted in the 1630s.
Other highlights include a rarely-shown portrait of Lady Margaret Stuart, Countess of Nottingham, by Paul van Somer, which dates from about 1620 and shows her wearing an elaborate dress with an improbably-plunging neckline, which experts said demonstrated her power and status.
The exhibition is set to run until December 2025 and is free to enter.