Now the old school gates at the landmark on Calton Hill in Edinburgh are set to be revived - more than half a century after the relocation of the Royal High School to another site.
More than two months of sensitive repair and restoration work by blacksmiths has enabled the gates - which were so encrusted with rust they had completely seized up - to be reopened.
The work, instigated by Edinburgh’s Hidden Door festival, means the building’s main entrance on Regent Road will be able to be used for the first time in decades for the 10-day event next month.
The gates have been brought back to life in the first stage of restoration work at the building, which is due to become a new National Centre of Music in the next few years.
A spokeswoman said: “The restoration of the former Royal High School gates is a key part of the legacy Hidden Door will leave as part of this year’s festival.
“They are an original architectural feature and allowed for people to approach the building as was intended by architect Thomas Hamilton.
“The restoration work being carried out is being done in a way that minimises damage to the gates and the surrounding stonework, whilst maintaining as much of the original fabric as possible.”
A team of volunteers is carrying out an extensive clean-up of the building for Hidden Door, which will be transformed by a programme of music, theatre, dance, spoken word and visual art.
Festival manager Hazel Johnson said: “It’s very exciting to be able to restore and reopen the original main gates to the building.
"They’re such beautiful structures and the kind of gate people peer through and never expect to see what's on the other side. They were pretty much rusted shut – you couldn’t really see where the rust ended and the gate began.
“When we had the opportunity to open them up again we thought it would be good to get them working properly and looking as best as they possibly can.
"Everyone coming to Hidden Door will now be able to come into the building from Regent Road again and explore it from there.
"We’re going to be opening up every single nook and cranny”
Blacksmith Colin Thomasson, who has led the restoration project, said: “The construction of these gates pre-dates the Forth Bridge – it’s amazing that they've survived for so long.
"They were just a mass of rust before any work was carried out, but I’ve loved working on them over the last couple of months.”
The Edinburgh World Heritage trust has helped Hidden Door pay for the work on the gates.
Catriona O’Neill, associate architect at Simpson & Brown, the Edinburgh-based architectural practice working on the long-term restoration of the former school, said: "The gate restoration work has presented the opportunity to closely inspect the intricacies of the historic gate ironwork obscured by decades of rust and paint, and devise a carefully considered repairworks strategy.
"This is important work - not only for providing access to the upcoming festival, but for the ongoing conservation of this prestigious building and its enjoyment by future generations."