An old Russian proverb says that the thirst for power is the hardest to quench. Ivan Shishman, Ivan Alexander's frstborn son from his second marriage, craved power. But his proved to be a short brush with power. He succeeded his father to the throne in Turnovo, but the state had become a shadow of one-time great Bulgaria. Almost all ties with the other two Bulgarian states, Ivan Sratsimir's Vidin principality and the Dobroudja principality of Despot Dobrotitsa, had been severed. Ivan Shishman's struggle to survive under the pressure of the Ottoman offensive soon turned into a desperate and valiant, though hopeless fight.
At the end of September 1371 a messenger brought the news that at the village of Chernomen in the valley of the Maritsa river, Sultan Murad's army had defeated the troops of the brothers Vulkashin and Uglesha from Macedonia. The two defeated nobles were the first to face and fight the invader. The Turks ravaged the Bulgarian lands, leaving terror and ruin behind them. Ivan Shishman watched them conquer Macedonia and the Rhodopes, aware that he was not strong enough to help Bulgarian strongholds in the Rhodopes against the assailants. Northern Thrace and the Zagore region also fell prey to the invader. "And indeed, those still alive were envying those already dead...," wrote the monk Issay.
The son of Ivan Alexander was to suffer the consequences of dissent between him the Balkan rulers. Ivan Shishman himself, in the face of the common threat, found it hard to extend a hand to his neighbors. He was compelled to make peace and to suffer the humiliation of becoming vassal to the Sultan, even allowing the Sultan to marry his sister Kera Tamara. Soon afterwards the Turks violated the treaty. After heavy fighting, Ivan Shishman surrendered Ihtiman, Samokov and Sofia. He fought desperately to defend the western part of the Balkan range, but Murad's troops overran Nish and Prilep and headed for the heart of the Balkans.
Only then did Ivan Shishman and the other Balkan rulers manage to join forces. King Lazar of Serbia, the Bosnian King and Despot Ivanko of Dobroudja offered an alliance to Ivan Shishman, which he entered though unable to supply troops. In 1387 the allied Christian forces routed the Turks at Plocnik (Serbia), proving that the Sultan's army was not immune to defeat. Tsar Ivan Shishman could heave a sigh of relief, see to his rump of a kingdom and encourage Patriarch Euthymius to keep the Turnovo art school going, to the glory of Bulgaria in the Slavic world.
However, the Turkish army, once recovered from the defeat, took the offensive again. It penetrated the Balkan passes and conquered some of northeastern Bulgaria around the fortress of Drustur on the Danube. Ivan Shishman was forced to confirm his submission as vassal to the Sultan. After the tragic defeat of the Christian army at Kossovo Pole (Serbia) in June 1389 the Bulgarian troops returned home fewer in number and frustrated. The defeat of the allied Christian forces paved the way for total Balkan domination by the Ottoman Turks.
The Tsar in Turnovo was in a bind. He was a good warrior and diplomat, but he was not strong enough to prevent the Ottoman conquest. In July 1393, after three months in siege under the courageous leadership of Patriarch Euthymius, the capital Turnovo finally fell. In the besieged stronghold of Nikopol, the Tsar heard of the massacred boyars and of the population sold as slaves. Ivan Shishman held this last piece of Bulgarian land in the ancient fortress on the Danube for months, while Turkish attempts to crush the resistance failed. But so did Ivan Shishman's efforts to form an alliance with the Hungarian King Sigismund against the Turks. He watched the principality of Dobroudja collapse and the invaders close the ring around the Vidin kingdom. The Second Bulgarian State was perishing before his eyes.
In 1395 Ivan Shishman finally succumbed to the army of Sultan Murad and died in captivity. The Bulgarian people sang songs about Tsar Ivan Shishman and his army which took the blow and temporarily saved Europe from the Ottoman invaders.