It is located along the Line Wall Curtain and was built to protect Gibraltar Harbour against enemy attack.

In 1758 the main face of the bastion held six guns intended to defend the Old Mole firing out to ships 600–700 yards (550–640 m) away.

[1] During the Great Siege of Gibraltar, the bastion was redesigned and enlarged to become a demi-bastion featuring a retired flank behind an orillon with parapets 12 feet (3.7 m) thick [1] In the 1790s, Sir William Green oversaw improvements to Gibraltar's defences and had the Orange and the Montagu Bastions extended and also arranged for a counterguard to be constructed in front of them as additional defences.

[3] A third layer of protection was added by constructing a breakwater in front of the counterguard to deter amphibious assaults.

[1] Between 2006 and 2008 the bastion was subject to major restoration work as part of the Government of Gibraltar's city walls walk scheme As part of the restoration works, two Victorian RML guns from the nearby King's Bastion were relocated here.