This is my first timeline so I would be thankful for any advice.
The Preface
The kingdom of Hungary-Croatia as it was known among the Croatian nobles was since its inception an unstable thing. Separate identities, culture and language kept the two apart. Not to mention they were often on the opposite sides of the many power struggles for the throne among the Arpad ruling family. Hoping to solidify their power the Kings started to act against the agreement their predecessor Coloman made with the Croatian noble houses and in the second half of the 13th century things were starting to get out of hand. Several powerful houses had become hereditary rulers of their zhupanias and feeling secure in their strongholds they began to oppose central government of the failing Arpad dynasty. Andrew III ascended to the throne in July 1290 and was immediately opposed by several other claimants. Among these was Queen Mary of Naples, sister of the late king. In her support many nobles of Croatia rose in rebellion and supported the claim of her son Charles Martel as king. Civil war would rage on for twenty years as claimants would seek to secure their hold on the throne. This state of chaos allowed the noble family of Shubichi to rise to pre-eminence in Croatia. Both Andrew and Charles tried to secure the loyalty of the powerful Shubichi by granting their patriarch Paul, who had also been the Ban of Croatia since 1273, complete rule of the lands between the Gvozd Mountain and river Neretva in 1293. All other nobles in Croatia became vassals of Paul and his title of Ban became hereditary as did his newly acquired possession. The death of Charles Martel in 1295 diffused the situation and there was a lull in the fighting until 1299 when Andrew tried to make his uncle his successor. That same year Paul conquered Bosnia becoming probably the most powerful magnate in all of kingdom of Hungary-Croatia. The fighting continued and in August 1300 Paul’s brother George was sent to Naples to bring Charles Robert, son of the late Charles Martel, to Croatia. Next year upon the death of Andrew III he was crowned king with the support of Paul and Ugrin of the house of Czak. Charles would not be without an opponent because most of the Hungarian magnates refused to acknowledge him and elected Wenceslaus of Bohemia as king Ladislaus V. During the siege of Buda in 1302 Charles defeated Ladislaus V, who relinquished his claim to the throne in return for his life. Yet only a month later the young Charles was dead from pneumonia and pandemonium reigned in the kingdom once more. As it was before several claimants tried to take the throne. These were Ladislaus V, Otto III of Bavaria, Stephen Dragutin of Srem and Robert of Calabria, uncle of the late Charles and heir to the kingdom of Naples.
But Paul would have none of it. In December 1302 he summoned the Croatian Sabor and Sabor of the whole of Slavonia as well as leading nobles of Bosnia in the town of Bihach. After winning over Stephen Baboneg, the most powerful magnate of Slavonia, by promising him the hereditary title of Ban of Slavonia Paul is declared king by the joint Sabor. Over the coming days internal matters of the kingdom are settled. Both Sabors are reformed and joined into a single Sabor of Kingdom of Croatia with representatives from Croatia, Dalmatia, Slavonia and Bosnia. His co-brother-in-law Stephen Kotroman is restored to the position of Ban of Bosnia. Paul sends a delegation to Stephen Dragutin, his father-in-law, informing him of his support to his claim to the throne of Hungary. In return Dragutin declares kingdom of Croatia no longer part of his inheritance. On Easter 1303 in the royal basilica in Solin Peter IX the Archbishop of Split crowned Paul with the Croatian royal crown as Paul Tomislav II king of Croatia and lord over Dalmatia, Slavonia and Bosnia. His claim would be challenged by Doge Pietro Gradenigo and Robert of Clabaria but both would fail. Following Paul’s victory over Venice in 1311 and capture of Zadar his titles were confirmed by Pope Clement V securing his reign. While the realm of Paul would consolidate over the coming years Hungary would remain a realm divided until the mighty Habsburgs would enter the game early in the 15th century.
What do you think does this have potential?