At the beginning of the 19th century the Ottoman Empire included all of the Balkan Peninsula north to the southern edge of the Hungarian Plain, but by 1914 had lost all of it except Constantinople and Eastern Thrace to the rise of Balkan nationalism, which saw the independence of Greece, Serbia, the Danubian Principalities and Bulgaria. What empire included all of the Balkan Peninsula north to the southern edge of the Hungarian Plain at the beginning of the 19th century?