Serbia started to disintegrate after the death of Stefan Dušan.
According to Matteo Villani, an unidentified Serbian lord sought Hungarian assistance against his more powerful (and also unnamed) enemy in the late 1350s.
Historians John V. A. Fine and Pál Engel write that the Serbian lord was a member of the Rastislalić family; Gyula Kristó and Iván Bertényi identify him as Lazar Hrebeljanović.
Royal charters of 1358 show that Hungarian troops fought in Serbia in October 1358.
The next summer Louis also marched to Serbia, but Stefan Uroš V of Serbia avoided battle.

Louis and the royal army stayed in Transylvania in November 1359 and January 1360, implying that he planned a military expedition against Wallachia or another neighboring territory.
A charter of 1360 said that a Romanian voivode, Dragoș of Giulești, restored Louis's suzerainty in Moldavia after a rebellion of local Romanians.
According to most Moldavian chronicles, Dragoș, who is sometimes identified with Dragoș of Giulești and sometimes as Dragoș of Bedeu, departed "from the Hungarian country, from Maramureș" at the head of his retinue, crossed the Carpathian Mountains while chasing an aurochs and settled in the valley of the Moldova River in 1359.
The same chronicles presented this "dismounting" by Dragoș as a decisive step towards the development of the Principality of Moldavia.
Another Romanian voivode, Bogdan, who had rebelled against Louis and plundered the estates of the Romanian landowners loyal to the king already in the 1340s, departed from Hungary and invaded Moldavia in the early 1360s.
Bogdan expelled the descendants of Louis's vassal, Dragoș, from the principality.
According to John of Küküllő, Louis launched several expeditions against Bogdan, but their dates cannot be determined.
Bogdan ruled Moldavia as an independent prince.

Upon the pope's request, Louis sent Hungarian troops to relieve Bologna, which was besieged by Bernabò Visconti's troops.
After Visconti lifted the siege, Louis's mercenaries pillaged the region and refused to cooperate with the papal legate; Louis had the commander of the army imprisoned.
After a conflict emerged between Emperor Charles IV and Rudolf IV, Duke of Austria, rumors spread about a conspiracy to dethrone the emperor in favor of Louis or Rudolf.
Charles IV, Rudolf IV and Louis met in Nagyszombat (now Trnava in Slovakia) in May. The emperor and the duke mutually surrendered their claims to the other party's realms.
Louis also persuaded the emperor to renounce his suzerainty over the Duchy of Płock in Poland.

Louis decided to convert the Jews in Hungary to Catholicism around 1360.
After experiencing resistance, he expelled them from his realms.
Their immovable property was confiscated, but they were allowed to take their personal property with them and also to recover the loans they had made.
No pogrom took place, which was unusual in Europe in the 14th century, according to historian Raphael Patai.

Emperor Charles IV and Rudolf IV of Austria signed a treaty of alliance against the patriarch of Aquileia, who was Louis's ally, in August 1361.
Fearing the formation of a coalition along the western borders of Hungary, Louis asked his former enemy, Louis of Taranto (Joanna I's husband), to send at least one of his brothers to Buda, and mediated a reconciliation between Rudolph IV and the patriarch.
At a meeting with Louis's envoys in Prague, Emperor Charles made an insulting remark about Louis's mother, stating that she "was shameless", according to Jan Długosz's chronicle.
Louis demanded an apology, but the emperor did not answer.

In preparation for a war against Bohemia, Louis ordered the mobilization of the royal army and marched to Trencsén (now Trenčín in Slovakia).
However, his supposed allies (Rudolf IV of Austria, Meinhard III of Tyrol and Casimir III of Poland) failed to join him, and the emperor initiated negotiations that lasted for months with the mediation of Casimir III.
Louis was finally reconciled with Charles IV at their meeting in Uherské Hradiště on 8 May 1363.

Louis invaded Bosnia from two directio
Serbia started to disintegrate after the death of Stefan Dušan. According to Matteo Villani, an unidentified Serbian lord sought Hungarian assistance against his more powerful (and also unnamed) enemy in the late 1350s. Historians John V. A. Fine and Pál Engel write that the Serbian lord was a member of the Rastislalić family; Gyula Kristó and Iván Bertényi identify him as Lazar Hrebeljanović. Royal charters of 1358 show that Hungarian troops fought in Serbia in October 1358. The next summer Louis also marched to Serbia, but Stefan Uroš V of Serbia avoided battle.
Louis and the royal army stayed in Transylvania in November 1359 and January 1360, implying that he planned a military expedition against Wallachia or another neighboring territory. A charter of 1360 said that a Romanian voivode, Dragoș of Giulești, restored Louis's suzerainty in Moldavia after a rebellion of local Romanians. According to most Moldavian chronicles, Dragoș, who is sometimes identified with Dragoș of Giulești and sometimes as Dragoș of Bedeu, departed "from the Hungarian country, from Maramureș" at the head of his retinue, crossed the Carpathian Mountains while chasing an aurochs and settled in the valley of the Moldova River in 1359. The same chronicles presented this "dismounting" by Dragoș as a decisive step towards the development of the Principality of Moldavia. Another Romanian voivode, Bogdan, who had rebelled against Louis and plundered the estates of the Romanian landowners loyal to the king already in the 1340s, departed from Hungary and invaded Moldavia in the early 1360s. Bogdan expelled the descendants of Louis's vassal, Dragoș, from the principality. According to John of Küküllő, Louis launched several expeditions against Bogdan, but their dates cannot be determined. Bogdan ruled Moldavia as an independent prince.
Upon the pope's request, Louis sent Hungarian troops to relieve Bologna, which was besieged by Bernabò Visconti's troops. After Visconti lifted the siege, Louis's mercenaries pillaged the region and refused to cooperate with the papal legate; Louis had the commander of the army imprisoned. After a conflict emerged between Emperor Charles IV and Rudolf IV, Duke of Austria, rumors spread about a conspiracy to dethrone the emperor in favor of Louis or Rudolf. Charles IV, Rudolf IV and Louis met in Nagyszombat (now Trnava in Slovakia) in May. The emperor and the duke mutually surrendered their claims to the other party's realms. Louis also persuaded the emperor to renounce his suzerainty over the Duchy of Płock in Poland.
Louis decided to convert the Jews in Hungary to Catholicism around 1360. After experiencing resistance, he expelled them from his realms. Their immovable property was confiscated, but they were allowed to take their personal property with them and also to recover the loans they had made. No pogrom took place, which was unusual in Europe in the 14th century, according to historian Raphael Patai.
Emperor Charles IV and Rudolf IV of Austria signed a treaty of alliance against the patriarch of Aquileia, who was Louis's ally, in August 1361. Fearing the formation of a coalition along the western borders of Hungary, Louis asked his former enemy, Louis of Taranto (Joanna I's husband), to send at least one of his brothers to Buda, and mediated a reconciliation between Rudolph IV and the patriarch. At a meeting with Louis's envoys in Prague, Emperor Charles made an insulting remark about Louis's mother, stating that she "was shameless", according to Jan Długosz's chronicle. Louis demanded an apology, but the emperor did not answer.
In preparation for a war against Bohemia, Louis ordered the mobilization of the royal army and marched to Trencsén (now Trenčín in Slovakia). However, his supposed allies (Rudolf IV of Austria, Meinhard III of Tyrol and Casimir III of Poland) failed to join him, and the emperor initiated negotiations that lasted for months with the mediation of Casimir III. Louis was finally reconciled with Charles IV at their meeting in Uherské Hradiště on 8 May 1363.
Louis invaded Bosnia from two directio
Louis I of Hungary