War of Hungarian Succession (Premysloides Dynasty)

Background
Tragic and decisive battle of Vas where were killed King Stephen, Crown Prince Ladislau and number of Hungarian nobles, commenced new Hungarian civil war. War on Succession, but also war of form of Hungary. War was led between three sides.

Andrewits
Loyalists supporting youngest song of King Stephen, Duke Andrew. Most of these loyalists were recruited from Cumans and Cuman-like aristocracy living in Hungary and from closest allies of Stephen V. Andrewits wanted to continue in Stephen dynastic line and build decentralized, loose kingdom with weak position of ruler, that allow Cuman tribes to free movement and life in Hungary.

Stephanites
Formed from Regency Council, supporters of centralized kingdom under rule of ambitious Stephen the Posthumous, son of King Andrew II (grandfather of Stephen V). Very hostile toward Roman Empire and pledge to fight against imperial influence and rule over Voivodina, if they win.

League
League fought against both sides, as they were supporters of change governing system in Hungary from tribal-feudal kingdom in to oligarchic confederative republic with rule of parliament of nobles, oligarchs and magnates. Confused in their perception of Roman Empire, as they had strong sympathy to imperial support of cities, merchants and trade, but were hostile toward centralized imperial regime.

War
Civil War undergone from mid-April 1270 to December 1278 and changed in to brutal anarchy and destruction of unprecedented scale. Andrewits ruled Central Hungary and Carpathia, League ruled over Western Hungary and claimed also lost Vas, while Stephanites formed their core in south Hungary and near Balaton. Aba, Csák, Koszegis and Babonić family hired large mercenaries corps, while Andrewits had Cuman cavalry and paganic hordes, include various small Mongol factions and Stephanites assembled remnants of King Stephen Army, local levies and foreign volunteers.

After four dozens battles and sieges, war ended inconclusive and only with total destruction of Hungary. When destruction peaked, Polish High Duke Leszek, nameless Galician Duke and Templars intervened to stop war. Templars attacked Stephanites, raided their capital city Osijek and killed members of Regent Council and Stephen the Posthumous. Galicians and Polish armies defeated League Army near Zalaegerszeg and captured most of League oligarchs and magnates, while Leszek army with mercenaries led strike against Andrewits and annihilated Cuman horde and tribal rule in Eastern Hungary and executed Stephen son, Andrew.

Aftermath
After this intervention, Templars, Leszek and Galician Duke appointed new ruler of Hungary, obscure great-great-grandson of Stephen III, Lászlo, who was coronated as new king and was granted enormous sum of money confiscated from defeated sides to build loyal army and centralize power in Hungary.

Lászlo I, later known as "Lászlo the Cruel", "Lászlo the Usurper", "Lászlo the Mad", "Lászlo the Savior" or "Lászlo the Great", led active, strong-willed and ruthless policy toward former oligarchs, nobles and autonomous provinces. He also builded new capital city, connected Hungary with Roman Empire, negotiated favourable trade and cooperation agreements with Poland and Roman Empire, supressed various rebellions and unrests, executed enormous number of "enemies of realm" (about 5,000 executed) and builded various hospitals and orphanage. In his late years, he became senile and more cruel and to fill orphanage, he ordered killing parents and sending their children to these orphanages. He was poisoned by unknown killer.

War itself was terrible anarchy for Hungary. Most estimates show death or harm of about 25% of Hungarian population only because of war (350,000 persons). Agriculture and supplying collapsed and famine spread in Hungary and killed another 100,000 people. Full-scale famine was prevented only because massive shipments of grain from Holy Roman Empire and Roman Empire bought by confiscated gold. Also, about 90% of mining and production output collapsed and Hungary became one of most impoverished region in Europe.