In 1453, the Eastern Roman Empire fell behind, and the Holy Roman Empire, located in central Europe, had to face the invasion of the Turks directly. The Turks are keen to expand, and although they believe in Islam, they think they are the real "Roman emperors", the throne of the Holy Roman Empire, which has been in power by the Habsburg dynasty for 200 years, and they are the last defenders of the Christian world. The two sides fought each other in Vienna: one side vowed, the other vowed to defend to the death.