Editing Fort Blockhouse (section)

===Early fortifications (1431–1667)===
Following the burning of [[Portsmouth]] during the [[Hundred Years' War]], money was set aside in 1417 to provide protection for Portsmouth Harbour. A timber [[blockhouse]] was first built on the Gosport side of the harbour in 1431, after authorisation by [[Henry VI of England|Henry VI]]. A chain was strung from Blockhouse point to a similar tower in Portsmouth, which could be raised to prevent entry to the harbour by enemy ships.<ref>{{cite book|url= https://books.google.com/books?id=47iheRUGKIEC&pg=PA89   |title= English Castles A Guide by Counties|first= Adrian|last= Pettifer |year= 1995|publisher=Boydell Press|page=89|isbn=978-0851157825}}</ref> It was subsequently rebuilt and strengthened, and in 1542 [[John Leland (antiquary)|John Leland]] described it as a round stone tower with [[artillery|ordnance]].<ref name="GGTower">{{cite web |title=Gosport Tower |url=https://gatehouse-gazetteer.info/English%20sites/1274.html |website=Gatehouse Gazetteer |access-date=20 August 2024}}</ref>

Around the year 1539 a 'bulwark' was built by [[Thomas Spert]] to the south-west of the blockhouse (where Haslar Hospital now stands);<ref name="Colvin1982" /> it was subsequently known as Lymden's Bulwark.<ref name="GGBulwark">{{cite web |title=Lymden's Bulwark |url=https://www.gatehouse-gazetteer.info/English%20sites/5011.html |website=Gatehouse Gazetteer |access-date=20 August 2024}}</ref> Further to the south another fort was built in 1545-46 named [[Fort Monckton#Haselworth Castle (1545-1556)|Haselworth Castle]], though this was abandoned only eleven years after construction.<ref>{{Cite web|url=http://www.mygosport.org/gosport_history.htm|title=My Gosport guide to the History of Gosport Hampshire|website=www.mygosport.org}}</ref> The [[Cowdray engraving]] of ''The Encampment of the English forces near Portsmouth'' in 1545 depicts all three structures, with Haselworth still under construction;<ref name="Colvin1982">{{cite book |last1=Colvin |first1=Howard |title=The History of the King's Works: 1485-1660 (part II) |date=1982 |publisher=Her Majesty's Stationery Office |location=London |pages=500–513}}</ref> two years later the 1547 [[Inventory of Henry VIII]] lists 'Lymden's Bulwark by the West Haven, under Captain John Lymden' and also 'Hasillworth Castle', but the blockhouse is omitted (implying it was no longer armed at this time).<ref name="GGTower" /> By the end of the century all these fortifications were in a derelict state, and a few decades later only a mound remained to indicate the site of the former bulwark.<ref name="GGBulwark" />