When opposition grew in 1688 against the Catholic King James II, the military establishment around Portsmouth was controlled by the King's illegitimate son, James FitzJames, the Duke of Berwick. Revolution broke out and for a period Portsmouth and its defences were important to the King as a potential exit route for the Royal Family to France; by late December, however, this route was no longer needed. George Legge, the Baron Dartmouth, pressurised FitzJames to hand over control of Southsea Castle to the Protestant Captain Carter on 18 December and Portsmouth surrendered to the revolution two days later. The traveller Celia Fiennes, who visited the castle in 1690, observed that it was "very fine, but I think it is but of little strength and service."