Since the Treaty of Utrecht, which had ended the last major European war, Britain had been an ally of France, a strong reversal in policy, as France had previously been considered the premier enemy of Britain. The reasons for the alliance were complex, and many had doubted the détente could last long, but when Newcastle became Secretary of State, they had been allies for nearly a decade. By 1719, they had become part of a wider Quadruple Alliance, which was by far the most powerful force in European politics, as had been demonstrated during the War of the Quadruple Alliance, a largely-naval war in the Mediterranean by which the powers had defeated a Spanish attempt to reclaim lost territory in Italy. The alliance was unpopular, however, with many in Parliament and in the country, which continued to consider France to be Britain's natural enemy.