Ivan Kőszegi (Hungarian: Kőszegi Iván, German: Yban von Güns; died 5 April 1308) was an influential lord in the Kingdom of Hungary at the turn of the 13th and 14th centuries. Earlier historiographical works also refer to him Ivan Németújvári (Hungarian: Németújvári Iván, German: Ivan von Güssing, Croatian: Ivan Gisingovac). He was Palatine in 1281, between 1287 and 1288, and from 1302 until 1307, Ban of Slavonia in 1275, from 1284 until 1285 and in 1290, and Master of the treasury in 1276 and 1291.
Originating from the powerful Kőszegi family, his career was characterized by series of rebellions and violations of the law against the royal power. As one of the so-called oligarchs, he established a province in Western Transdanubia, which laid in the borderlands of Hungary with Austria, and ruled Győr, Sopron, Moson, Vas and Zala counties de facto independently of the monarchs by the 1280s. Beside his rebellions in Hungary, he waged wars with the Duchy of Austria too. Because of his plundering and looting raids against the Styrian provinces, he was dubbed as "greedy wolf" by the Austrian chronicles. During the era of feudal anarchy, he usually played a role of "kingmaker". For instance, he invited Andrew the Venetian to the throne against the reigning Ladislaus IV of Hungary three times (1278, 1287, 1290). He initially supported Andrew III after his accession to the throne, but from 1292 he turned against the king and became a partisan of the pretender, Charles Martel, Duke of Salerno. After the extinction of the Árpád dynasty in 1301, he betrayed the House of Anjou too and played an important role in the subsequent succession war as the partisan of Wenceslaus, then Otto.
Ivan (also John) was born in the 1240s into the wealthy and influential Kőszegi family, originating from the gens (clan) Héder, as one of the four sons of the powerful lord Henry I Kőszegi. His brothers were Nicholas I, Henry II – who were also elevated into high dignities during the age of the late Árpáds – and Peter, the Bishop of Veszprém from 1275 till his murder in 1289.
His marriage to an unidentified noblewoman produced three children. His eldest son was Gregory, who held some minor offices before predeceasing him in 1297. He left two sons, Nicholas III and Andrew, who inherited Ivan's wealth and dominion in 1308. Ivan also had an unnamed daughter, who married a certain Dominic, a familiaris of her father. This Dominic fought in the Battle of Göllheim in 1298. Some historians identified him with Dominic Csák. During his advanced age, Ivan's younger son John the "Wolf" was born in the 1300s; after his downfall in Hungary, he integrated into the Austrian nobility, becoming ancestor of the Bernstein (or Pernstein) family. Ivan also had an illegitimate son, Nicholas, who was born in 1282 from an extramarital affair. Nicholas served as Bishop of Győr from 1308 to 1336.
Ivan Kőszegi first appeared in contemporary records in March 1265, when he participated in the Battle of Isaszeg alongside his father Henry and brother Nicholas. During the civil war between Béla IV of Hungary and his son Duke Stephen, Ivan's father was a staunch supporter of the king and led the royal army against the duke. However Stephen gained a decisive victory over his father's army, and Henry Kőszegi and his two sons were captured. His defeater Pousa Tengerdi presented the fettered prisoner Ivan Kőszegi in the ducal court of Stephen following the clash. The Kőszegis were being held as prisoners and after the Battle of Isaszeg, Béla IV was forced to accept the authority of Stephen in the eastern parts of the kingdom. On 23 March 1266, father and son confirmed the peace in the Convent of the Blessed Virgin on 'Rabbits' Island and Henry and his two sons, alongside others, were released from captivity.
Stephen V ascended the Hungarian throne in May 1270, following his father's death. In response, the king's sister Anna seized the royal treasury and fled to Bohemia. Several magnates and Béla's closest advisors followed her and left Hungary, including Henry Kőszegi, who handed over Kőszeg, Borostyánkő (Bernstein, Austria) and other castles along the western borders to Ottokar II. In the same time, Ivan Kőszegi also handed over his "two castles called Sztrigó" (today Štrigova, Croatia), which laid in Zala County, to the Bohamian king. Henry and his sons had spent the next two years in exile at Ottokar's court in Prague. Their departure caused a war between Hungary and Bohemia, which lasted until the conclusion of an agreement in Pressburg in July 1271. According to their treaty, Stephen V promised that he would not assist Ottokar's opponents in Carinthia, and Ottokar II renounced the castles he and his partisans held in Hungary. The royal armies soon recaptured Kőszeg, Borostyánkő and other fortresses along the western border of Hungary. Ivan Kőszegi was knighted by Ottokar during his exile, according to the Steirische Reimchronik.
Henry Kőszegi and his sons returned from Bohemia to Hungary following Stephen's death in the summer of 1272. His ten-year-old son Ladislaus IV ascended the throne. During his minority, many groupings of barons fought against each other for supreme power. The arriving Henry Kőszegi brutally murdered Ladislaus' cousin, Béla of Macsó, the only adult male member of the Árpád dynasty. The Kőszegis entered alliance with the Gutkeleds and the Geregyes, forming one of the two main baronial groups (the other one was dominated by the Csák and Monoszló clans). Ivan's father became a key figure in the early stage of the era of so-called feudal anarchy. When Henry extended his dominance in the royal council, Ivan served as ispán of Zala County – where his initial lands mostly laid – from September 1272 to March 1273 (with a short interruption in November 1272). In this capacity, he participated in private initiative Hungarian incursions into Austria and Moravia, Ottokar's realms in February 1273, along with Matthew Csák, Denis Péc, Joachim and Amadeus Gutkeled. Ivan was involved in the skirmishes against Styria and Carinthia. After the siege of Fürstenfeld, Matthew Csák turned against Carinthia, while Ivan commanded his troops into Styria. His army besieged Waltersdorf and Scenleurench. Thereafter, Ivan functioned as ispán of Sopron County between June 1273 and September 1274. In retaliation for Hungarian incursions, Ottokar's troops invaded the borderlands of Hungary in April 1273. They captured Győr and Szombathely, plundering the western counties. The royal council sent Joachim Gutkeled and Ivan Kőszegi to recapture the castle of Győr. Kőszegi also participated in the battle at Laa in August. However Ottokar II launched a successful retaliatory strike in the autumn of 1273, and seized many fortresses again, including Győr and Sopron. Ivan and Nicholas Kőszegi led a small-size army, which crossed the river Morava and attacked a Bohemian unit at Marchegg. They also unsuccessfully besieged the castle there. As ispán of Sopron County, Ivan organized the line of defense against the invading forces. He commanded a royal relief army, which assisted to defend the castle of Kobersdorf (Kabold). Ivan, who, in order to gain time, offered a duel with a third of himself against three knights including Henry, Count of Pfannberg, successfully defended Kapuvár (German: Valbach) by destroying the dam at the river Vág (Váh) and flooding the surrounding area. Thereafter he fought in Pereszteg and Lós, harassing the invading Bohemian army with hit-and-run tactics. He unsuccessfully tried to recapture Sopron from the Bohemian troops. Ivan was also present at the siege of Győr.
Ivan lost influence for a brief time after the Battle of Föveny in late September 1274, when Peter Csák defeated the united forces of the Kőszegis and the Gutkeleds. Henry Kőszegi was killed, but his sons Nicholas and Ivan managed to flee the battlefield, withdrawing their troops to the borderlands between Hungary and Austria. Thereafter Peter Csák and the young Ladislaus IV gathered an army against the Kőszegis' domain in the autumn of 1274; their troops marched into Western Hungary, pillaging the brothers' landholdings. Nicholas and Ivan barricaded themselves in the castle of Szalónak (present-day Stadtschlaining, Austria). The royal army besieged the fort, but failed to capture it because of the coming winter. Through his ambitious and unscrupulous sons, the Kőszegi family survived their paterfamilias' death.