The conquest of Thrace by the Ottomans and the defeat of the allied Christians at the Maritza were as great blows to the Bulgarians as to the Greek Empire, though they had given no assistance to the allies. The occupation of Adrianople and Philippopolis opened the way to a further advance into Bulgaria and Macedonia. It was not, however, till 1366 that Murad availed himself of this advantage, and commenced the series of attacks which ultimately made him master of Macedonia and of a great part of Bulgaria and Serbia. The position of affairs in the peninsula at this time was very favourable to him. The Bulgarians, Serbians, Bosnians, and Greeks were madly jealous of one another; each of them preferred the extension of the Ottoman rule to that of their rivals. Bulgaria alone, if united, might have successfully resisted Murad. But in 1365 its Czar, Alexander, died, and his kingdom was divided between his three sons. Sisman, the elder, got the largest share. The other two gave no assistance to their brother when the Ottomans invaded his country. Between 1366 and 1369, Murad advanced into Bulgaria, and took possession of the Maritza Valley, as far as the Rhodope Mountains. In 1371 Lalashahin encountered an army of Bulgarians and Serbians at Samakof, not far from the city of Sofia, and completely defeated it, with the result that Bulgaria, up to the Balkan range, was annexed to the Ottoman Empire. It remained so for over five hundred years, till its release in our own times. After this great victory at Samakof, Lalashahin was instructed by Murad not to pursue his conquest of Bulgaria north of the Balkan range, but to proceed westward, and, in concert with Evrenos, to invade Macedonia as far as the River Vardar. This occupied the two generals in the years 1371-2. Kavalla, Druma, and Serres fell into their hands. In 1372 they crossed the Vardar River and penetrated into Old Serbia, Albania, and Bosnia. The main part of Serbia, however, remained in the hands of Lazar, its prince. But he was compelled to acknowledge the suzerainty of the Sultan. As regards the part of Bulgaria not annexed, its prince, Sisman, was allowed to retain his independence. His daughter entered the harem of Murad, with the understanding that she was not to be compelled to adopt the Moslem religion. It was not till 1381 that a further advance was made by Murad. He then sent his armies across the Vardar River and captured Monastir. He also took possession of Sofia, and in 1386 of Nisch, after a fierce struggle with the Serbians. 3. MURAD’S ACQUISITIONS IN ASIA MINOR.