Castle Islands Fortifications , Bermuda Several of the islands strung across the South entrance of Castle Harbour , Bermuda were fortified in the early days of the territory , hence the harbour ' s name . When official settlement of the archipelago by England began in 1612 ( unofficial settlement having begun with the 1609 wrecking of the Sea Venture ) the first permanent town , St . George ' s ( then called " New London " ) was placed on the North side of St . George ' s Harbour . St . George ' s Harbour could be accessed directly by channels from the East . Those channels , however , were shallow , suitable , originally , only for small ships . As a consequence , and despite any major settlement on its shores , Castle Harbour was an important anchorage in the early years of the colony , with its main entrance , Castle Roads being an important route in from the open Atlantic for shipping . It was also a weakpoint , as it was remote from the defences of St . George ' s Harbour , and difficult to reach . It was quickly fortified and garrisoned by a standing militia . Initial fortification by the Virginia Company ' s ( Bermuda was originally settled as an extension of Virginia ) first deliberate settlers in 1612 , was around the inlets to St . George ' s Harbour , but by the end of that year work had commenced on Castle Harbour ' s defences , starting at Castle Island ( previously called " Gurnett ' s Head " , and " King ' s Island " ) . As a temporary measure , two guns had been salvaged from the 1609 wreck of the Sea Venture , one of which was installed on Castle Island ) in 1612 . Proper fortifications were soon raised under the instructions of Governor Richard Moore . King ' s Castle is , today , the oldest surviving English fortification in the New World . It is Bermuda ' s oldest standing stone building , predating the State House . Its " Captain ' s House " , built a year after the State House , in 1621 , is the oldest stone home in Bermuda . It is also the oldest standing English house in the New World . In 1614 , King ' s Castle famously replulsed Spain ' s only ever attack on Bermuda . Two shots were fired from its artillery . although neither struck , the Spanish vessel abandoned the attack ( its crew did not realise that the gunners in the fort had only enough ammunition for one more shot ) . This fort was used as late as the Second World War by Bermuda ' s military garrison , with soldiers living in tents within its walls , watching over the channels with machine guns . Other forts built at the South of Castle Harbour included " Devonshire Redoubt " ( 1620 ) and the " Landward Fort " , on Castle Island , " Southampton Fort " ( 1620 ) , on " Brangman ' s Island " ( originally known as " Moore ' s Island " and " Southampton Island " ) , at the East side of Castle Roads , " Old Castle " , or " Charles ' Fort " , ( 1615 ) , on Goat Island , " Pembroke Fort " , on Cooper ' s Island , and Fort Bruere , on the Main Island . At Ferry Reach , on the north of Castle Harbour ( an area now separated by the Causeway ) , " Burnt Point Fort " , or " Ferry Point Battery " ( in 1688 ) , and " Ferry Island Fort " ( in the 1790s ) were built , and in 1822 a Martello Tower . Ferry Island Fort and the Martello tower were both built by the regular British Army , which had established a permanent Bermuda Garrison following US Independence ( although detachments had been posted in Bermuda almost continuously since 1701 ) . The island chain across the South of Castle Harbour ( which includes Castle Island ) is often referred to as the " Castle Islands " . Their fortifications are the oldest surviving English New World fortifications ( due primarily to their being constructed of stone , whereas contemporary English fortifications on the North American continent were built from timber and earth ) . They were also the first English coastal fortifications in the New World . Those then existing were depicted and described in the 1624 book , The Generall Historie of Virginia , New - England , and the Summer Isles , by Captain John Smith . As a result of their historical significance , they have been made a UNESCO World Heritage Site , together with St . George ' s Town and other nearby fortifications , like Fort St . Catherine ( " " ) .