AN extensive archaeological dig will try to uncover the remains of Sheffield Castle where Mary, Queen of Scots spent almost a third of her life as a prisoner.

Sheffield Castle was a giant mediaeval fortress that dominated the South Yorkshire city but was demolished during the English Civil War, otherwise known as the War of the Three Kingdoms.

Sheffield City Council yesterday announced an £800,000 revamp of the Castlegate Quarter, which will include a fresh dig on the castle site so closely linked with Mary.

Most people who know about Mary are aware she was imprisoned in Fotheringhay Castle in Northamptonshire prior to her execution at the age of 44 in 1584.

For much of the previous 14 years, however, Scotland’s only queen prior to the Union of the Crowns in 1603 was mainly imprisoned in Sheffield Castle, the remains of which are known to lie under a particularly ugly 1960s development known as Castle Markets.

Taken to Sheffield in 1570, Mary was kept captive by the Earl of Shrewsbury, who owned the castle and other properties that Mary was allowed to visit.

The only visible remains of Mary’s ancient prison were locked in basements under the concrete structure of Castle Markets in the area known as Castlegate.

There had been a castle, bridge, market and houses on the site since the Norman Conquest, and the area was once the centre of trading, commerce, local government, law and order, trade, transport and hospitality but declined in the 20th century.

The indoor Castle Market closed in 2013 and was demolished in February 2015. It was replaced by the Moor Market.

The council said £786,000 from its Capital Growth Fund would kickstart a revamp of the area over the next 18 months, giving it “new life” as a digital business hub while also celebrating its history.

Over the past few years the whole of the Castlegate area of Sheffield has undergone redevelopment, including the demolition of the markets.

The new works will also include the uncovering of the underground River Sheaf, which gave Sheffield its name.

Mazher Iqbal, council cabinet member for business and investment, said: “This package of projects demonstrates the importance we place on the future of Castlegate as a key part of the city centre economy and in the partnership which has come together to achieve it.

“Castlegate is a major gateway into the city centre, but at the moment it doesn’t reflect the incredible regeneration happening elsewhere in the centre, such as The Moor and Sheffield Retail Quarter.”

It is the intention of various groups to study and highlight the connection of Sheffield Castle to Mary, Queen of Scots.

Over the 14 years of her captivity in Sheffield her entourage varied from 15 to 42, and while she was allowed to receive guests and even spend summer holidays at Buxton spa for treatment for her various ailments, her life in the castle was truncated.

She had to give an hour’s notice to leave her quarters for basic exercise, and her guards were numerous and changed each day at 5am.

“This severe confinement would go on for year in, year out with only brief remission periods, much to detriment of Mary’s health,” according to the Sheffield Timewalk website, which adds: “Her everyday life was very restricted as she was kept in such close confinement. She read books and wrote many letters.”

Martin Gorman, chairman of the Friends of Sheffield Castle, said: “This is fantastic news, and we are excited that work to excavate the remains of Sheffield’s medieval castle will begin soon.”