Britain fought the war against Napoleon on the high seas, enlarging its Royal Navy from 135 ships in 1793 to 584 in 1812, and expanding personnel from 36,000 seamen in 1793 to 114,000 in 1812. In spring 1814 Napoleon surrendered, the allies restored the Bourbon kings to the throne, and France was no longer an enemy of Great Britain. The naval war was over and Britain could now sharply reduce its Royal Navy. It had no need to impress sailors, and never again used that means of forced recruitment, although it did not officially renounce the practice. By the time of Britain's next major war, against Russia in 1853, a new system of fixed-term engagements had given the Royal Navy a sufficient number of volunteer recruits to meet its manpower needs. Throughout the remainder of the 19th century changes in manpower needs and improved conditions of service permitted the Royal Navy to rely on voluntary enlistment to meet its requirements, augmented by the recall of reservists when necessary. This continued to be the case until World War I, when organised conscription was introduced in 1916 for all the military services.