The Siege of Vienna in 1683 was one of the decisive turning points in European history. It was the last serious threat against Western Christendom, and its repercussions were so significant that countries normally jealous and hostile towards each other set aside their differences to repel the armies of Islam and their fierce allies, the Tartars. The consequences of the defeat were severe: the Ottomans lost half of their European provinces, and a long period of decline began, leading to the eventual collapse of their Empire. The Habsburgs shifted their focus from France and the Rhine borders to the Balkans. The hot September of 1683 marked the last great confrontation between the Cross and the Crescent and was destined to open a new era in European history, which lasted until the Cataclysm of World War I in 1914.