The local population, left without protection by the Byzantine government, organized its defence on its own. The Bulgarian feudal lord Momchil rejected the suzerainty of the Byzantine Emperor and established his rule over the entire Rhodope region and part of the Aegean coast. Momchifs several big victories over the Ottomans won him great popularity and his fame rivalled that of Ivailo before him. His army consisted not only of men from the regions directly afflicted by Turkish incursions but also of discontented peasants from all over Bulgaria. Constantinople became even more afraid of Momchil’s men than of the Turks. A Byzantine-Turkish alliance against the rebellious boyar was hastily concluded and the small state of Momchil, who had risen to the position of a genuine popular leader, was wiped away.
Two feudal lords from Macedonia
After Momchil, two feudal lords from Macedonia – Vukashin and Ouglesh – decided to cross swords with the Ottomans but they were utterly defeated in a battle near Chernomen, not far from Adrianople, and fell in that bat-tle, after which Murad I advanced to the north and northeast, entering the territory of Bulgaria. Here, however, the conquerors came up against unexpectedly strong resistance put up not so much by the troops of the Tsar as by local commanders of strongholds and by the population itself. The Ottomans needed moie than ten years to traverse the route between Plovdiv and. Sofia. The cities of Yambol, Karnobat, Sofia, Bitola, the strongholds in the Rhodope Mountains of Tsepena and Rakovitsa and many others put up particularly strong resistance. Sofia fell in 1382, only after the Turks had managed by deceit to take prisoner Ban Yanuka, the extremely capable Leader of its defence. With the hope of preventing the further penetration of the Turks into Bulgaria, Tsar Ivan Shishman became vassal to Murad I.
When the Asian conquerors reached the centre of the Balkans, the rulers of Serbia and Bosnia were frightened and concluded an alliance for joint action against Murad. The united Serbian and Bosnian troops dealt a crushing blow to the Turks in the big battle near the town of Plochnik in 1387. The Bulgarian Tsar joined the Serbo-Bosnian alliance which provoked an immediate wrathful reaction on the part of the Sultan. In 1388 a numerous Turkish army crossed the Balkan Range and conquered almost the whole of Northeastern Bulgaria without the city of Varna. Tsar Shishman was forced to reaffirm his vassal dependence from the Sultan and the terrible Ottoman hordes again set out for Serbia. In a battle which broke out at Kossovo Pole Murad I found his death but the Serbian troops, which had been joined by several Bulgarian feudal lords, were routed. Serbia also fell under vassal dependence from Turkey.