Byzantine–Hungarian War (1180–1185)

The Byzantine–Hungarian War of 1180–1185 was a conflict fought between the Byzantine Empire, under emperors Manuel I Komnenos and later Andronikos I Komnenos, and the Kingdom of Hungary, ruled by King Béla III. The war stemmed from a deterioration of relations between the two powers following the death of Manuel I in 1180.

Manuel I had held considerable influence over Hungary during his reign, acting as a guardian of the young Béla III. He had intended for Béla to succeed him as emperor, marrying him to his daughter Maria Komnene and granting him the title of despotes. However, the birth of Manuel's son, Alexios II Komnenos, altered these plans. Following Manuel's death, the regency council surrounding the young Alexios II was unstable and unable to maintain the same level of influence over Hungary.

Béla III, freed from Byzantine influence, reverted to an independent foreign policy. He seized Byzantine territories in the Balkans, specifically the regions of Dalmatia and Sirmium, which had been disputed for centuries. The Hungarian campaigns were facilitated by internal instability within the Byzantine Empire, marked by struggles for power among the imperial family and the subsequent reign of terror under Andronikos I Komnenos.

The war saw limited large-scale battles, characterized more by sieges and raids. Byzantine attempts to retake lost territories were hampered by internal strife. Hungarian success in securing Dalmatia and Sirmium effectively ended Byzantine control over these regions. While Andronikos I attempted to stabilize the empire and prepare for a counter-offensive, his brutal rule led to his overthrow and death in 1185, further destabilizing the Byzantine state and paving the way for the collapse of Komnenian rule.

The war concluded inconclusively, with Hungary retaining control of the seized territories. The Byzantine Empire, already weakened by internal conflicts, was unable to effectively challenge Hungarian dominance in the region. The conflict marked a significant shift in the balance of power in the Balkans, diminishing Byzantine influence and strengthening Hungary's position.