On today's date in 1371, near Chernomen, the troops of Valkashin and Uglesha were defeated by the Ottomans, led by Lala Sahin. The victory of the Ottomans stabilized their position in the Balkans and virtually eliminated the only resistance east of Nis. Over the next decade, Ottoman possessions in the Balkans would expand steadily, until 1387, when Murad I's forces were defeated by the combined armies of Serbia and Bosnia at Plocnik. For Bulgaria, the victory of the Ottomans meant the looming of an imminent threat that coincided with the death of Ivan Alexander a few months earlier.
This is what Dr. Alexander Stoyanov writes about "Military History" ;.
When in 1364 Amadeo of Savoy captures Gallipoli, the Ottoman dominions are defacto divided into two parts – Rumelia, where the capital Edirne is located and Anatolia – Ottoman possessions in Asia Minor. Sources and historians speculate on the whereabouts of the Ottoman ruler Murad during the period when the Dardanelles were outside Ottoman control. But most likely the Sultan was “isolated“ in Asia Minor, while his possessions in Europe were under the control of the leaders of the various Ghazi detachments (see the article on the early Ottoman army in the latest issue of “Military History”). The main leader of these war-adventurers was Lala Shahin, Murad's teacher and loyal servant. Lala Shahin showed himself as a talented general and despite the limited means at his disposal, he managed to stabilize and protect the Ottoman possessions in the Balkans until in 1374. the Byzantines did not return Cimpe and Gallipoli to the Ottomans. The victory at Chernomen played a key role in this stabilization.
When in 1355 the most notable Serbian ruler died – Stefan Uros IV, called Dušan, his kingdom began to disintegrate, with vast territories in Macedonia and northern Greece being divided between various, semi-independent, despots related to the ruling Nemanic dynasty. Some of these despots were so independent that they even claimed royal titles of their own. This was exactly the case with the brothers Valkashin and Uglesha Mrniavcevic, who controlled the territories of today's Republic of Macedonia. Valkašin claimed the title “King of Serbs and Greeks”, which was previously used by Dušan in opposition to Dušan's son Stefan Uros V Slabi.
After, in the forties of the 14th century, the Ottomans managed to destroy the possessions of Duke Momchil, who controlled White Sea Thrace and the Rhodope Mountains, they continued their expansion with the capture of Didymotica (Dimotika) and Arkadiopol (Lyuleburgaz), with which they finally established themselves in Thrace . Soon gangs of ghazis began to attack the possessions of the Macedonian despots, and Valkashin and Uglesha, feeling threatened by the new enemy, set about gathering an army with which to defeat the Ottomans and drive them out of Adrianople (Edirne). After in 1364 Amadeus of Savoy managed to capture Gallipoli and Cimpe, the Ottoman position in the Balkans was seriously shaken. This was a signal for Uglesha and Valkashin, and they began to collect the necessary funds for the march. The army was ready in 1371, although its numbers remain unclear. According to different sources, the figure varies from 20 to 70,000 thousand, but probably both assumptions are wrong. We should not forget that the Mrnjević brothers, although the strongest among the Macedonian despots, had limited resources. Four decades earlier, Mikhail Shishman, at the head of the still united Bulgarian state, mustered no more than 17,000 men for the campaign against the Serbs, most of them mercenaries. To suppose that two despots with a limited territory could mobilize a larger army than the Bulgarian tsar, who inherited a full treasury from the Terterians, would be naive. The logistics we mentioned yesterday also play their part. In this sense, we can rather assume that the despots could hardly have gathered more than 10-12,000 people, a figure which in itself was impressive considering the fragmentation of the Balkan territories.
On the other hand, the number of Ottomans is greatly underestimated, with some historians relying solely on Ottoman sources and offering a figure of 800 people. Such a claim is ridiculous, for the simple reason that even with a night attack, as happened at Chernomen, 800 men would inflict defeat on the enemy, but not defeat him and put him to complete flight. The contrary would suggest that the Ottomans had some kind of commandos who possessed extraordinary fighting skills, weapons and coordination for their time. On the other hand, all are unanimous, though by different figures, that the size of the Ottoman forces was half that of the Serbs. The difference came in quality. Unlike the ill-disciplined militias that supplemented the Serbian heavy cavalry, the Ottomans had an army composed mostly of professional warriors with long experience in fighting, pillaging, ambushing, and outwitting the enemy. Judging by the successes achieved by Lala Shahin before and after the Battle of Chernomen, we can conclude that the Ottoman forces, remaining “detached” in the Balkans were composed of the more experienced part of the Ghazis serving Murad. There is a serious dose of logic in this, considering that the Balkans were the main theater of Ottoman expansion, and it was here that the Ghazis faced the most serious resistance and received more serious booty. Logically, the most experienced warriors were drawn to this front in order to achieve fame and gain riches, as well as attain a place in paradise through war with the infidels. Therefore, the Ottomans had a smaller but better prepared army.
Valkashin and Uglesha decided to take advantage of Murad's absence and the limited number of opposing units and conquer Edirne, thereby eliminating the Ottoman threat. Their plan was to make a secret march and attack the enemy by surprise. For this purpose, their army followed the river Maritsa. Lala Shaheen, an old veteran and experienced in rough terrain combat, moved to prevent the enemy's advance. He sent the necessary scouts, something the unwary Serbs did not do, and set about waiting for an opportune moment to strike first against the enemies. This sought-after moment appeared on the night of September 25-26, when the Christian troops encamped near Maritsa indulged in feasting and forgot to set up posts, confident of their numerical superiority. Lala Şahin's forces waited until their enemies were properly drunk, and in the early hours of the 26th, the Ottomans attacked their half-asleep, drunken enemies. A massacre followed, in which Vlashin and Uglesha also died, and that part of their army that was not slaughtered suffocated, fleeing to the river Maritsa. With a single blow, Lala Sahin liquidated an entire army, forever depriving the Macedonian despots of the possibility of gathering another such force. Indeed, for the next ten years no further march was made into Macedonia, but when Sofia fell in 1382, and Murad's armies marched westward, the lands along the Vardar were conquered quickly and without serious resistance. Only Marko, son of Valkashin, temporarily kept his possessions, serving as a faithful vassal of Murad, and then of his son Bayazid. This same Marko later covered himself with the glory of a national hero for Serbs and Bulgarians under the name Krali Marko.