Vladislaus was the firstborn son of Vladislaus Jagiełło and his fourth wife, Zofia (Sonka) Holszańska. He ascended the throne at the age of ten and was immediately surrounded by a group of advisors headed by Cardinal Zbigniew of Oleśnica, who wanted to continue to enjoy his high status at court. In spite of that, the young ruler and his ambitious mother were aware that there was opposition to them. Despite the agreements signed between Władysław Jagiełło and the Polish magnates to ensure the succession for his sons, the opposition wanted another candidate for the Polish throne - Friedrich of Brandenburg, who was betrothed to Jadwiga, Jagiełło's daughter by his second wife. However, the conspiracy was resolved by the death of the princess, rumoured to have been poisoned by Sonka Holszańska.
The young king's reing was difficult from the very outset. Even during his coronation, the ceremony was interrupted by a hostile nobleman, one Spytko of Melsztyn. On the next day, the customary homage of the townsfolk of Cracow did not take place due to a dispute between the temporal and spiritual lords of Mazovia over their place in the retinue. Neither did Vladislaus have much to say later about matters of state, which were run by the powerful Cardinal Zbigniew of Oleśnica. The situation did not change even after parliament gathered in Piotrków in 1438, and declared the fourteen-year-old king as no longer in his minority.
This situation continued until 1440, when Vladislaus was offered the crown of Hungary. However, accepting it would have led to numerous problems. Hungary was under a growing threat from Turkey and some Polish magnates did not want to agree to the king of Poland also being the monarch of Hungary, while Elisabeth, widow of the deceased king of Hungary, Albrecht Habsburg, attempted to keep the crown for her yet unborn child. Such inconveniences aside, Vladislaus finally took the Hungarian throne, having engaged in a two-year civil war against Elisabeth. He had received significant support from Pope Eugenius IV, in exchange for his help in organising an anti-Turkish crusade. The eighteen-year-old king, although thus far a king solely by title, became deeply involved in the crusade, paying no heed to the interests of Poland and of the Jagiellonian dynasty.
The "bulwark of Christianity" and other slogans put forward by the papal envoy Giuliano Cesarini, together with an enticing promise of victory in a glorious crusade for God, persuaded Vladislaus to engage in a two-year war against the Ottoman power. He also accepted the argument that the ten-year truce signed in 1443 in Szeged was not valid since the infidel Turks could not be trusted to keep their word. Despite their significant military advantage, Vladislaus failed to recognise the serious threat which the Turkish empire posed for the entire Europe. Therefore, when the Battle of Varna began on 10 November 1444, the Polish king did not sense that this would be his final fight. He was killed during the charge on the ranks of the janissaries, who were protecting their sultan.
