few more impressive works in the north of England, but in general the fortifications were limited in scale. 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. Calshot Castle was designed to protect 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 forts that William Fitzwilliam, the Lord Admiral, and William Paulet decided to build to improve the defences along the Solent; the others were at East and West Cowes, and Hurst. Calshot was constructed on the narrow Calshot Spit, overlooking the deep-water channel running through into Southampton. Temporary earthwork defences and gun batteries were erected as an interim measure, but the castle itself was built quickly and finished by the end of 1540. It probably reused stone and lead from Bealieu and Netley abbeys, which had recently been closed during the Dissolution of the Monasteries. The castle initially had a garrison of eight gunners, five soldiers and a lieutenant, under the command of a captain. In the late 1540s, it was heavily armed by the standards of the time, with 36 pieces of artillery. In the 1580s, the castle caught fire and the timber needed for the repairs required 127 trees to be sent from the New Forest. The work was carried out in 1584, prompted by the threat of a Spanish invasion, but by that time its garrison had shrunk to eight men. 17th–19th centuries In the early 1600s, England was at peace with France and Spain and coastal defences received little attention. During the English Civil War of the 1640s, Calshot was held by Parliamentary forces against King Charles I, and protected with a 15-strong garrison at an annual cost of £107. Parliament considered the fortress important and kept it supplied