During the second half of the 19th Century the British designated four of their key ports with dockyards as being Fortresses. The location of these well defended harbours reflects the Eurocentric nature of British strategic concerns at that time, largely concentrated around the North Atlantic and Mediterranean Seas. The four Fortresses were in general terms:
Bermuda was settled by the English at roughly the same time that colony was set up in Jamestown by the Virginia Company operating under a Royal Charter. In 1615 the islands were named Somers Isles and came under the control of the Somers Isles Company and it is about this time that the first slaves were brought in. The population was mixed with indentured labourers from old |Spanish colonies, ship wreck survivors, prisoners from Ireland and Scotland as well as forcibly displaced people from Ireland.
In 1645 the English Civil War led to Bermuda siding with the Royalist cause. At the conclusion of this war the Parliamentarians ensured the island returned to their control.
Initially the staple product had been tobacco plantations, but these were quickly overtaken by production in Virginia, so there was a gradual move to maritime activities such as ship building. The Bermudians developed as a maritime nation with their sloop being adopted by the Royal Navy.
During the American War of Independence (1775 to 1783), Bermuda initially fell under suspicion as supporting the rebellion and by December 1775 all the armaments had been removed from the various fortifications on the islands.
By 1783 the Royal Navy started to improve their facilities in Bermuda and in 1811 work started on a large Royal Naval Dockyard. Work also started to fortify and garrison the islands. The defences were steadily developed over the next century but never came under attack. During World War 2 Bermuda was largely garrisoned by United States troops who built some new batteries and barracks.