A feud with the Hungarian Hunyadi family followed, embittered by John Hunyadi's failed attack on the forces of the Ottoman Empire at the Battle of Varna in 1444—while Ulrich remained idle—and Hunyadi's refusal to recognize Ulrich's claim to Bosnia on the death of King Tvrtko II (1443). In 1446 Hunyadi, now regent of Hungary, harried the Celje territories in Croatia-Slavonia; however his power was broken at the Second Battle of Kosovo in 1448, and Count Ulrich was able to lead a successful crusade, nominally in the Habsburg interest, into Hungary (1450).
In 1452, he forced Emperor Frederick III to hand over the boy king Ladislaus to his keeping, practically making him ruler of Hungary. In 1454 his power was increased by his succession to his father's vast wealth; and after the death of John Hunyadi at the Siege of Belgrade in 1456, he was named Captain General of Hungary by Ladislaus,[3] an office previously held by his rival.
Ulrich's triumph did not last: On 8 November, he entered the fortress of Belgrade with King Ladislaus; the next day he was killed by agents of John Hunyadi's son László in unknown circumstances. With him died the male line of the Counts of Celje.[4]
He was buried in the Minorite Church of St. Mary in Celje. The eulogy was delivered by the famous humanist rhetorician and prelate Johann Roth.[5]
Ulrich's estates were claimed by his widow Catherine, his son-in-law Matthias Corvinus - the younger brother of László Hunyadi - as well as Count John of Gorizia, and Emperor Frederick III of Austria, who outlived his rivals.
Ulrich's high ambitions were sharply criticized by Aeneas Sylvius (the later Pope Pius II), although his writings were politically minded, as he had served as the personal secretary of Emperor Frederick III at the height of his conflict with Ulrich.
On his mother's side, Ulrich was the closest surviving male descendant of Francesco I da Carrara, lord of Padua. However, he is not known to have ever pressed claim on the Carraresi inheritance.
Possessions
At the time of his death, Ulrich held around 12 towns, 30 market towns and 125 castles: around 20 in Carinthia, Carniola, and Slavonia each, and the rest mostly in Styria.[6][7] He owned around a third of all castles in modern-day Slovenia at the time.[8]
Some of his most important possessions are listed below.
^Jože Pogačnik, Starejše slovensko slovstvo (Maribor, 1980), pp. 472-76
^Drago Bajt, Marko Vidic, eds. Slovenski zgodovinski atlas (Ljubljana: Nova revija, 2011), pp. 89-90
^Peter Štih, Ulrik II. Celjski in Ladislav Posmrtni ali Celjski grofje v ringu velike politike, in Igor Grdina & Peter Štih, eds. Spomini Helene Kottanner (Ljubljana: Nova revija, 1999), pp. 14-41