John V took Constantinople and forced the abdication of Cantacuzene (d. 1383). At the same time Dusan, having taken Adrianople, advanced on the capital. His sudden death (1355) led to the disintegration of the Serbian Empire and to the removal of a great threat to the Greeks. On the other hand, it left the Christians an easier prey to the advancing Ottomans.
Battle of Kosovo Polje (Kossovo), in a valley in southern Serbia between Pristina and the Laba River, waged between Serbian and Ottoman forces (See 1389 (Traditionally June 15)). The Byzantine, Ottoman, and Serbian historical sources sharply conflict, though modern scholars believe that the battle was a draw. In any case, Serbia became an Ottoman vassal state and the Balkan Peninsula was opened to further Ottoman expansion.
an besieged Thessalonica.
