Tresco's Historic Monuments
Tresco is famed for its natural beauty, its mild climate and its exotic gardens, but this idyllic island has also been in the frontline of Britain’s defences since the 16th century. Due to the threat from the Spanish and the French, two Tudor forts (the Old Blockhouse and King Charles’ Castle) were built to defend the harbours at Old Grimsby and New Grimsby, where enemies would try to land their troops.
In the mid-17th century Tresco had a prominent role in the Civil War and saw fighting and bloodshed and Cromwell’s Castle was built in the early 1650s to strengthen the defences of New Grimsby harbour. From the 18th century onwards government military expenditure in Scilly was devoted to the major fortifications on St Mary’s, but during World War I a seaplane base was established at New Grimsby and part of its site is now occupied by accommodation for visitors.
For more information on Scilly’s rich military history read Defending Scilly by Mark Bowden and Allan Brodie (English Heritage 2011 £9.99)
http://www.english-heritage.org.uk/publications/defending-scilly/