Andrew III of Hungary made his maternal uncle, Albertino Morosini, Duke of Slavonia, in July 1299, stirring up the Slavonian and Croatian noblemen to revolt.
A powerful Croatian baron, Paul Šubić, sent his brother, George, to Italy in early 1300 to convince Charles II of Naples to send his grandson to Hungary to claim the throne in person.
The king of Naples accepted the proposal and borrowed 1,300 ounces of gold from Florentine bankers to finance Charles's journey.
A Neapolitan knight of French origin, Philip Drugeth, accompanied the twelve-year-old Charles to Hungary.
They landed at Split in Dalmatia in August 1300.
From Split, Paul Šubić escorted him to Zagreb where Ugrin Csák swore loyalty to Charles.
Charles's opponent, Andrew III of Hungary, died on 14 January 1301.
Charles hurried to Esztergom where the Archbishop-elect, Gregory Bicskei, crowned him with a provisional crown before 13 May. However, most Hungarians considered Charles's coronation unlawful because customary law required that it should have been performed with the Holy Crown of Hungary in Székesfehérvár.

Charles counted his regnal years from this coronation, but Hungary had actually disintegrated into about a dozen independent provinces, each ruled by a powerful lord, or oligarch.
Among them, Matthew Csák dominated the northwestern parts of Hungary (which now form the western territories of present-day Slovakia), Amadeus Aba controlled the northeastern lands, Ivan Kőszegi ruled Transdanubia, and Ladislaus Kán governed Transylvania.
Most of those lords refused to accept Charles's rule and proposed the crown to Wenceslaus II of Bohemia's son and namesake, Wenceslaus, whose bride, Elisabeth, was Andrew III's only daughter.
Although Wenceslaus was crowned with the Holy Crown in Székesfehérvár, the legitimacy of his coronation was also questionable because John Hont-Pázmány, Archbishop of Kalocsa, put the crown on Wenceslaus's head, although customary law authorized the Archbishop of Esztergom to perform the ceremony.

After Wenceslaus's coronation, Charles withdrew to Ugrin Csák's domains in the southern regions of the kingdom.
Pope Boniface sent his legate, Niccolo Boccasini, to Hungary.
Boccasini convinced the majority of the Hungarian prelates to accept Charles's reign.
However, most Hungarian lords continued to oppose Charles because, according to the Illuminated Chronicle, they feared that "the free men of the kingdom should lose their freedom by accepting a king appointed by the Church".
Charles laid siege to Buda, the capital of the kingdom, in September 1302, but Ivan Kőszegi relieved the siege.
Charles's charters show that he primarily stayed in the southern parts of the kingdom during the next years although he also visited Amadeus Aba in the fortress of Gönc.

Pope Boniface who regarded Hungary as a fief of the Holy See declared Charles the lawful king of Hungary on 31 May 1303.
He also threatened Wenceslaus with excommunication if he continued to style himself king of Hungary.
Wenceslaus, left Hungary in summer 1304, taking the Holy Crown with him.
Charles met his cousin, Rudolph III of Austria, in Pressburg (now Bratislava in Slovakia) on 24 August.
After signing an alliance, they jointly invaded Bohemia in the autumn.
Wenceslaus who had succeeded his father in Bohemia renounced his claim to Hungary in favor of Otto III, Duke of Bavaria on 9 October 1305.

Otto was crowned with the Holy Crown in Székesfehérvár on 6 December 1305 by Benedict Rád, Bishop of Veszprém, and Anton, Bishop of Csanád.
He was never able to strengthen his position in Hungary, because only the Kőszegis and the Transylvanian Saxons supported him.
Charles seized Esztergom and many fortresses in the northern parts of Hungary (now in Slovakia) in 1306.
His partisans also occupied Buda in June 1307.
Ladislaus Kán, Voivode of Transylvania, seized and imprisoned Otto in Transylvania.
An assembly of Charles's partisans confirmed Charles's claim to the throne on 10 October, but three powerful lords—Matthew Csák, Ladislaus Kán, and Ivan Kőszegi—were absent from the meeting.
In 1308,
Andrew III of Hungary made his maternal uncle, Albertino Morosini, Duke of Slavonia, in July 1299, stirring up the Slavonian and Croatian noblemen to revolt. A powerful Croatian baron, Paul Šubić, sent his brother, George, to Italy in early 1300 to convince Charles II of Naples to send his grandson to Hungary to claim the throne in person. The king of Naples accepted the proposal and borrowed 1,300 ounces of gold from Florentine bankers to finance Charles's journey. A Neapolitan knight of French origin, Philip Drugeth, accompanied the twelve-year-old Charles to Hungary. They landed at Split in Dalmatia in August 1300. From Split, Paul Šubić escorted him to Zagreb where Ugrin Csák swore loyalty to Charles. Charles's opponent, Andrew III of Hungary, died on 14 January 1301. Charles hurried to Esztergom where the Archbishop-elect, Gregory Bicskei, crowned him with a provisional crown before 13 May. However, most Hungarians considered Charles's coronation unlawful because customary law required that it should have been performed with the Holy Crown of Hungary in Székesfehérvár.
Charles counted his regnal years from this coronation, but Hungary had actually disintegrated into about a dozen independent provinces, each ruled by a powerful lord, or oligarch. Among them, Matthew Csák dominated the northwestern parts of Hungary (which now form the western territories of present-day Slovakia), Amadeus Aba controlled the northeastern lands, Ivan Kőszegi ruled Transdanubia, and Ladislaus Kán governed Transylvania. Most of those lords refused to accept Charles's rule and proposed the crown to Wenceslaus II of Bohemia's son and namesake, Wenceslaus, whose bride, Elisabeth, was Andrew III's only daughter. Although Wenceslaus was crowned with the Holy Crown in Székesfehérvár, the legitimacy of his coronation was also questionable because John Hont-Pázmány, Archbishop of Kalocsa, put the crown on Wenceslaus's head, although customary law authorized the Archbishop of Esztergom to perform the ceremony.
After Wenceslaus's coronation, Charles withdrew to Ugrin Csák's domains in the southern regions of the kingdom. Pope Boniface sent his legate, Niccolo Boccasini, to Hungary. Boccasini convinced the majority of the Hungarian prelates to accept Charles's reign. However, most Hungarian lords continued to oppose Charles because, according to the Illuminated Chronicle, they feared that "the free men of the kingdom should lose their freedom by accepting a king appointed by the Church". Charles laid siege to Buda, the capital of the kingdom, in September 1302, but Ivan Kőszegi relieved the siege. Charles's charters show that he primarily stayed in the southern parts of the kingdom during the next years although he also visited Amadeus Aba in the fortress of Gönc.
Pope Boniface who regarded Hungary as a fief of the Holy See declared Charles the lawful king of Hungary on 31 May 1303. He also threatened Wenceslaus with excommunication if he continued to style himself king of Hungary. Wenceslaus, left Hungary in summer 1304, taking the Holy Crown with him. Charles met his cousin, Rudolph III of Austria, in Pressburg (now Bratislava in Slovakia) on 24 August. After signing an alliance, they jointly invaded Bohemia in the autumn. Wenceslaus who had succeeded his father in Bohemia renounced his claim to Hungary in favor of Otto III, Duke of Bavaria on 9 October 1305.
Otto was crowned with the Holy Crown in Székesfehérvár on 6 December 1305 by Benedict Rád, Bishop of Veszprém, and Anton, Bishop of Csanád. He was never able to strengthen his position in Hungary, because only the Kőszegis and the Transylvanian Saxons supported him. Charles seized Esztergom and many fortresses in the northern parts of Hungary (now in Slovakia) in 1306. His partisans also occupied Buda in June 1307. Ladislaus Kán, Voivode of Transylvania, seized and imprisoned Otto in Transylvania. An assembly of Charles's partisans confirmed Charles's claim to the throne on 10 October, but three powerful lords—Matthew Csák, Ladislaus Kán, and Ivan Kőszegi—were absent from the meeting. In 1308,
Charles I of Hungary