Over the years, the British built gun batteries that overlooked Rosia Bay to protect the harbour from attacking vessels. Parson's Lodge Battery, at the south end of the bay, is the largest of those defences and dates to the 18th century. The battery has a dominant position on a promontory in front of the southwestern corner of the Victualling Yard. The underlying cliffs were scarped by engineers to prevent attackers from climbing them. At one time, the battery housed three 18-ton 10 rifled muzzle-loading guns. It also provided storage for ammunition and living quarters. Parson's Lodge Battery is now under the aegis of the Gibraltar Museum.