The British policy which emerged was a close alliance with France, but one subject to the balance of power on the Continent, and in particular the preservation of Belgian independence. If the northern powers supported William I by force, they would encounter the resistance of France and Britain united in arms. If France sought to annex Belgium, it would forfeit the British alliance and find herself opposed by the whole of Europe. In the end the British policy prevailed. Although the continent had been close to war, peace was maintained on London's terms and Prince Leopold of Saxe-Coburg, the widower of a British princess, was placed upon the throne of Belgium. Fishman says that the London Conference was "an extraordinarily successful conference" because it "provided the institutional framework through which the leading powers of the time safeguarded the peace of Europe."