The war ended in a Hungarian victory, as the armies of Louis I dealt a blow in Bulgaria not only to the Turks, but also to the Bulgarian ruler Ivan Shisman, who was allied with them in 1377.

His campaigns in the Balkans were accompanied by the spread of Roman Catholicism among the Orthodox Slavs, which led to opposition from virtually all the southern Slavic countries and the Romanian principalities.

Despite the success, Hungarian rule in northern Bulgaria was not consolidated, and Louis had to organise the Vidin province into a vassal state with his loyalist Ivan Stratsimir, because he could not effectively control it.

In 1371, in the battle of Maritsa, they annihilated the Bulgarians and their Serbian allies, making Ivan Shishman a vassal of the Turkish Sultan.

[citation needed] Louis's forthcoming campaign was leaked by Voivode Vladislav I of Wallachia and he immediately formed an alliance with Ivan Shishman and Sultan Murad I.

[citation needed] From Temesvár (now Timișoara), the army moved in two directions, one staying in Transylvania, the other marching through Banate of Szörény to Wallachia.

The king pushed into the interior of Romania via Mezősomlyó, where he won a great victory over the Ottoman and Bulgarian reinforcements of Vladislav's army under the leadership of Nicholas I Garai, the palatine of Valjevo.

Murad I, too, sent his soldiers on a campaign in Hungary for the sole purpose of assisting the Voivode of the Vojvodina and possibly gaining an insight into the Hungarian territories.

It seemed that even after the death of the king, Hungary was not seriously threatened by the enemy, although one or two stray raiding parties did appear on the borders, coming from Rumelia only for reconnaissance and plunder.

[3] Louis may have considered the Ottoman affair closed, because he diverted his attention from the Balkans and instead led his hordes eastwards to Poland.

In this campaign, Louis conquered Halych, which many Hungarian kings had coveted for centuries, and annexed it to his country as a voivodeship of Ruthenia.