Background
In the last decades of the 13th Century, anarchy fell to Hungary. Powerful barons ruled vast territories and usurped royal rights. The continuous efforts of the kings to re-establish royal power failed.
On January 14, 1301, Andrew III the Venetian died heirless. With his death, the royal line of Árpáds died out. The kingdom remained without a king, but at least it remained. It was not unusual that a kingdom ceased to exist after the dynasty died out, but, in Hungary, the ideology of the kingdom remained strong and all of the oligarchs (in Latin: reguli, little kings) agreed that Hungary needed a king. They all agreed that this had to be a powerless king.
 | The Battle of Rozhanovce |
The king of Hungary had to be the descendant of the Arpad kings. Authority of the Arpad dynasty was still unquestionable. There were three candidates: Venceslaus Premysl, the son of the king of Bohemia, Otto Wittlesbach of Bavaria, and Charles Robert d’Anjou from Naples. After the struggles of the interregnum, Charles I was generally recognized as king and had a valid coronation on August 27, 1310. Though Charles I was a king, he had no real power. The reguli did not obey him. Peaceful solutions failed and the only way to regain royal power was war.
The most powerful and most notorious regulus, Matthew Csák of Trecin (Hung. Trencsén), openly rebelled against the king and forced him to relocate the royal seat from Buda to Timisoara (Hung. Temesvár) in 1311.
The Aba was an old aritocratic family in Hungary. One of them [Samuel I 1041-44] even became king as a brother-in-law of king St. Stephen I. At this time, they ruled over a large portion of Northern Eastern Hungary.
In autumn of 1311, Amádé Aba was killed by the citizens of Kosice (Hung: Kassa) because he tried to deprive the town of its royal priviliges and extended Aba power above the town. Some of his sons were captured and held in custody.
The sons of Amádé Aba wanted revenge, and the king, to "keep peace”, mediated between the Abas and Kosice (Kassa). In fact, the king supported Kassa and forced an agreement which would have crushed the Aba power. The sons of Amádé Aba did not accept the agreement and attacked Kosice (Kassa). The rebellion of the Abas was supported by Matthew Csák while other oligarchs remained neutral or nominally helped the king.
The Battle
The royal army and the rebels finally met near Rozhanovce (Rozgony). The Abas had approximately 4000 men, amongst them 1700 Moravian heavy cavalrymen, mercenaries sent by Matthew Csák. The others were also cavalrymen, mostly medium or light cavalry. The rebel army was led by "Big” Aba.
The king had ca. 3000 men. His army consisted of the medium/light cavalry of the lesser nobles, who preferred royal power instead of the local lord’s, the infantry of the local towns (mainly Kosice’s- the main target of the Abas), and the royal retinue of knights. The king was also helped by Hospitaller knights, who had at least 30 chapters in Hungary. The king personally led his army.
The battle began as a typical battle of the knights. Both armies tried to crush the enemy with a frontal cavalry charge. The Abas had more men and heavier cavalry, so they could push back royal forces. Even the royal standard bearer (Györke Csák) died and Charles had to continue fighting under the banner of the Hospitallers. The rebel cavalry nearly  | Charles I d'Anjou |
overwhelmed the royal cavalry. At this moment, the infantry of the townfolks, who were practically ignored by both the king and the Abas, side-attacked the rebels and managed to kill the rebel leaders. They saved the king and saved the day.
This was the first time in Hungarian military history that infantry played a decisive role in the outcome of a battle.
Aftermath
This was only the first step. In the following decade, the king defeated the reguli one by one. He practically had to conquer his own country. There was only one oligarch whom he couldn’t defeat. Matthew Csák managed to preserve his power, though he lost some of his territories. Charles was able to submit Csák domains only after the death of Matthew Csák.
Charles I consolidated royal power and his reforms became a strong base of a Golden Age in Hungarian medieval history under the reign of his son Louis I the Great. | 
