on 26 February 2021 as the sea cut into and compromised its foundations. The World Monuments Fund included the castle on their 2022 World Monuments Watch list of most endangered sites. In September 2022, it was one of six English castles included in a fundraising campaign by English Heritage to mitigate risks of destruction due to worsening coastal erosion. They hope to gather enough funds to repair and strengthen the sea walls around the castle. History 16th century Hurst Castle was built as a consequence of international tensions between England, France and the Holy Roman Empire in the final years of the reign of King Henry VIII. Traditionally the Crown had left coastal defences to local lords and communities, only taking a modest role in building and maintaining fortifications, and while France and the Empire remained in conflict, maritime raids were common but an actual invasion of England seemed unlikely. Modest defences based around simple blockhouses and towers existed in the south-west and along the Sussex coast, with a few more impressive works in the north of England, but in general the fortifications were limited in scale. Worsley's Tower, for example, built opposite the future site of Hurst Castle in the 1520s, was too small to hold powerful artillery and considered by surveyors in 1539 to be "one of the worst devised things" they had seen. In 1533, Henry broke with Pope Paul III over the annulment of his long-standing marriage to Catherine of Aragon. Catherine was the aunt of Charles V, the Holy Roman Emperor, who took the annulment as a personal insult. This resulted in France and the Empire declaring an alliance against Henry in 1538, and the Pope encouraging the two countries to attack England. An invasion of England appeared certain. In response, Henry issued an order, called a "device", in 1539, giving instructions for the "defence of the realm in time of invasion" and the construction of forts along the English coastline. Hurst Castle was designed to protect the western entrance to the Solent, a body of water that led from the English Channel to the naval base at Portsmouth and, through Southampton Water, to the important port of Southampton. The castle was one of four fortifications that William Fitzwilliam, the Lord Admiral, and William Paulet recommended building to strengthen the defences along the Solent; the others were at East and West Cowes, and Calshot. It