(who had been prime minister during the war but resigned in 1761) and the other leaders of the parliamentary opposition. The wedding was completed, but as a result of these machinations the prince remained in Britain for only thirteen days. Over the next few years the couple embarked on a wide-ranging tour of Europe, visiting many of the major states. In 1766 they went to France, where they were received by both his allies and recent battlefield enemies with respect. In Paris he made the acquaintance of Marmontel. The couple next proceeded to Switzerland, where they met Voltaire. The longest stop on their travels was Rome, where they remained for a long time exploring the antiquities of the city under the guidance of Johann Winckelmann. During their travels the couple also met Pietro Nardini and in 1767 the prince had his portrait painted by Pompeo Batoni. After a visit to Naples they returned to Paris, and thence to Brunswick. Ruler of Brunswick-Wolfenbüttel Restoration of state finances His father, Charles I, had been an enthusiastic supporter of the war, but nearly bankrupted the state paying for it. As a result, in 1773 Charles William Ferdinand was given a major role in reforming the economy with the assistance of the Geheimrat, Féronce von Rotenkreuz. They were highly successful, restoring the state's finances and improving the economy. This made the prince hugely popular in the duchy. When the American Revolutionary War broke out in 1775, Charles William Ferdinand saw an opportunity to replenish the state's treasury by renting its well-trained army to Great Britain. In 1776, Charles I signed a treaty supporting Britain in the war, the first prince to do so. Under the terms of this treaty, Brunswick-Wolfenbüttel supplied 4,000 troops for service with the British armies in America, under the command of general Friedrich Adolf Riedesel. Riedesel was given command of all the German troops serving in the Saratoga campaign, under British general John Burgoyne. Burgoyne was defeated in the Battles of Saratoga (1777), and his troops were taken captive as the Convention Army. Although the terms of surrender allowed the Convention Army to give their parole and return to Europe, the American Continental Congress revoked the convention. The Convention Army was kept in captivity until the war ended in 1783. Reign Charles I died in 1780, at which point Charles William Ferdinand inherited the throne. He soon became known as