The gates have stood at the entrance to Fort George since 1812
Now known as a luxury housing estate Fort George was originally built to house a garrison of British troops and protect St Peter Port harbour.
In the summer of 2010 the imposing gates underwent a facelift.
Historian Sylvia Brouard said the gates were opened by Lieutenant Governor Sir John Dodd in 1812, around 30 years after the fort was built.
The fort remained active until 1945 when Guernsey was liberated after the German Occupation.
The granite arch at the entrance of the fort is approximately 20ft (6m) thick and still features the same large gates that were installed in the early 1800s which, following a long process of restoration, are now fully operational again.
Clarence Battery is still visible as a fortified part of the area
When the fort was operational, behind the gate would have been a moat and drawbridge to provide a second line of defence against any invading force trying to gain access to the fort.
Sylvia explained that Fort George was constructed as a replacement for Castle Cornet as the castle grew too small to house the number of troops and size of cannon required to defend the harbour from the threat of Napoleon's France invading.
The fort only saw its guns fired in anger once, according to Sylvia, in June 1944 when the United States Air Force bombed the fort to destroy the radar station there ahead of the D-Day assault on northern France.
Following Guernsey's demilitarisation after the Occupation, the fort was sold to property developers in the 1960s and was converted into the open market housing estate it is today, though structures such as the gates and Clarence Battery still remain as a reminder of it's military past.