The weakening temporal power of the papacy and the Holy Roman Empire demonstrated the difficulties of unifying such a diverse geographical area as the continent of Europe, even when the continent was under the threat of the Ottoman Empire. Thirty Years War ended the idea of a unified Christian Europe. The Peace of Westphalia and then the Treaty of Utrecht in 1713, concluding the War of the Spanish Succession (1701–14), laid the ground for the establishment of a sovereign state system in Europe.