JUST four years ago it was vandalised, on the verge of collapse and had deteriorated to the point that it was deemed worthy of a place on English Heritage's Buildings at Risk register.
However, thanks to almost 300,000 in grant money, the listed Rotunda at Wentworth Castle Gardens, near Barnsley, has now been restored and was officially reopened yesterday.
Until 2007 the castle gardens were off-limits to the public and the spectacular Rotunda was just one of several monuments that were hidden by overgrown bushes.
The redevelopment, funded by grants from English Heritage and the East Peak Innovation Partnership, has included extensive work on the colonnade roof and an oculus – a circular window that is a feature of classical architecture – fitted to illuminate the interior with daylight.
The marble floor inside, meanwhile, has also been reinstated with a black and white geometric pattern that is typical of the Georgian period, and repairs have been made to the stonework.
Heritage director at Wentworth Castle Gardens, Vicky Martin, said: "We are delighted that the Rotunda has been restored.
"Now that we have reinstated the floor and roof, it means that we can use the building and various uses are currently under consideration."
The 18th-century Rotunda, one of 26 listed buildings at the 500-acre park and gardens that is in the care of the Wentworth Castle Trust, is believed to have been modelled on the Roman temple of Vesta in Tivoli, Italy.
It was planned by Thomas Wentworth, the first Earl of Strafford, who created the Wentworth Castle estate between 1708 and 1739, but then built by his son William and completed in 1746.
The mayor of Barnsley, Margaret Sheard, who officially opened the restored Rotunda yesterday, said: "Over the years the Rotunda has been described as a mausoleum, even though it was never used for this purpose. Perhaps it was the cellar in the podium that created the rumour.
"Paintings of the 1750s show the Rotunda in its prime as a distant parkland eye-catcher.
"Time though took its toll. The Rotunda became ruinous, vandalised and hidden in scrub woodland for years."
Since Thomas Wentworth's time, the estate had slowly slipped into dereliction and the listed landscape, which includes a series of serpentine lakes designed to look like a river from the main house, remained almost totally out of bounds to visitors.
Even after the estate was taken over by Northern College, an adult education establishment, public access was discouraged as the site was unable to cope with the amount of traffic that would have been generated.
However, things changed after Wentworth Castle Gardens appeared on the BBC Restoration programme in 2003. The resulting publicity led to a multi-million-pound investment and the gardens then opened in 2007 with a new access road, a new car park and a visitors' centre.
Even after the gardens opened, though, several monuments within the estate were still in need of a revamp and the Wentworth Castle Trust is still in the process of gaining grant money to carry out further restoration.
Over the coming weeks, additional works are planned to take place at Wentworth Castle Gardens to make the estate more appealing for visitors.
Conservatory is next big target
Other restoration projects are also in the pipeline at Wentworth Castle Gardens.
In June 2008, the Wentworth Castle Trust applied for 5m of grants from the Heritage Lottery Fund to revamp both the glasshouse and walled kitchen garden, but this bid was turned down.
Now, the charity and the Friends of Wentworth Castle are trying to raise 1m towards the estimated 3.7m cost of revamping the Victorian conservatory, which was built in 1877 for Frederick William Thomas Vernon-Wentworth.
If this amount of money is raised, the trust can then apply for further Heritage Lottery funding of 2.7m.
A public fundraising scheme launched last year, to try and enable the restoration of the glasshouse, has included ventures such as asking people to sponsor a pane of glass.
More details about the restoration projects at Wentworth Castle Gardens is available by calling 01226 776040.