This forms part of the West Side Batteries defences and is situated on a cliff edge at a height of over 80 feet above sea level to the north of Napier of Magdala Battery, at the southern end of the Rock in the Rosia area. It was originally a small battery until 1770 when it was modified with a cannon mounted over a parapet, having a mattress placed in front of it in order to absorb any enemy fire. A drawing by the Chief Engineer of Gibraltar, Colonel William Green, exists which shows a plan and section of the works to be carried out on the site.
It was first mentioned as Engineer Battery in 1834 when it mounted two 32-pdrs. Major General sir John Jones in his report of 1841 (PRO WO 55/1554/3) recommended a sea battery of seven or eight guns on the rocky knoll between New Mole Port and Rosia but it seems nothing was done. Instead, in 1850 the two 32-pdrs had been replaced by a single 56-pdr, and subsequently by a 68-pdr in 1859. This in turn, and probably in 1863, was replaced by three 7-inch RBI guns, Nos 64, 216 and 282, which are reported in the battery in a Board of Ordnance Report dated 1867.