John I Albert

John I Albert (Polish: Jan I Olbracht; 27 December 1459 – 17 June 1501) was King of Poland and (disputed) Supreme Duke of Lithuania from 1492 to his death, as well as Duke of Głogów from 1491 to 1498. He was the fourth Polish sovereign from the Jagiellonian dynasty and the son of Casimir IV and Elizabeth of Austria. Related to the House of Habsburg, John Albert was groomed to become emperor in the Holy Roman Empire, a plan that ultimately failed. He was well-educated and tutored by scholars such as Johannes Longinus and Callimachus, whom he had subsequently befriended. Heavily influenced by the Italian Renaissance, John sought to strengthen royal authority at the expense of the Catholic Church and the clergy. In 1487, he led a force against the Ottoman Empire and defeated the Tatars of the Crimean Khanate during the early phase of the Polish–Ottoman War. In the aftermath of the Bohemian–Hungarian War, John Albert attempted to usurp Hungary from his elder brother Vladislaus, but on 20 February 1491, he renounced his claim to Hungary in exchange for the Duchy of Głogów and the suzerainty over half of Silesia. Casimir died in 1492, and John was passed over as the Grand Duke of Lithuania in favour of his younger Alexander, thus de facto breaking the personal union between the two nations, though John claimed the position of Supreme Duke. John was elected as the King of Poland on 27 August of the same year, after which to secure his succession to the Polish throne he had dispatched an army against the Piast princes from the Duchy of Masovia, which ensured his victory but alienated the higher nobles and magnates. He later invaded Masovia to deprive Konrad III of his ancestral holdings and curtail internal opposition to his rule....