Fort George was built by the British when Austrian Imperial authority in region was ceded to the French as a part of a humiliating peace settlement dictated by Napoleon. Fearing Napoleon would turn the Adriatic into a "French lake", with free rein to launch warships from the Venetian Arsenal and expand his empire further into Europe, the Royal Navy was sent to the Adriatic with a regiment of foot and detachment of artillery to prevent Napoleon's ambitions coming to fruition. The British had used the island of Vis for its fresh water and safe anchorage for a number of years prior the committing defences to the island. In 1811 the French successfully raided the bay of Vis inflicting damage to the town and destroying numerous merchant vessels. It was hence decided that the bay of Vis needed protection from further such attacks. Initial defences were built on Host Island in the middle of the harbour, consisting of two 18 pound guns in a stone fortification. In 1812 Fort George was begun after the British Governor, Colonel Robertson, decided that the harbour needed greater protection. Fort George was to be primarily a light cannon and musketry defence and was therefore built to cooperate with three further Martello towers; towers Bentick and Robertson to the rear of the fort and Wellington across the bay. Like the defences on Host Island, these Martello towers would carry large cannon able of deterring enemy ships from approaching the bay. The defense towers and Fort George were built under the supervision of Captain Henryson using labourers recruited directly from the island and remained strictly under the jurisdiction of the army whilst the battery on Host Island remained under the control of the Royal Navy. The defences were completed by late 1813 and two years later were handed to the Austrians, who had begun reclaiming control of their Adriatic territories following decline and eventual fall of Napoleonic forces in the region.