Hedwig Jagiellon (, ; 8 April 1408, Kraków – 8 December 1431, Kraków) was a Polish and Lithuanian princess, and a member of the Jagiellon dynasty. For most of her life she, as the only child of Wladyslaw Jagiello, was considered to be heiress of the Polish and Lithuanian thrones. After the birth of Jagiello's sons in 1424 and 1427, Hedwig had some support for her claims to the throne. She died in 1431 amidst rumors that she was poisoned by her stepmother Sophia of Halshany. Family relations She was the only daughter of King of Poland and Supreme Duke of Lithuania Wladyslaw Jagiello by his second wife, Anna of Celje, daughter of William, Count of Celje, and Anna of Poland. Anna of Celje was a granddaughter of King Casimir III of Poland and therefore a Piast heiress. Thanks to his marriage to her in 1402, Jagiello re-legitimized his rule as King of Poland after the death of his first wife, Hedwig (Jadwiga), who reigned as King (not Queen consort) of Poland. Jagiello's and Anna's only daughter, born in 1408, was named after Queen Hedwig. After it became apparent that Anna of Celje would not be able to bear any further children, Hedwig was officially proclaimed heir presumptive to the throne during a congress in Jedlnia in early 1413. Queen Anna died in 1416, leaving Hedwig as Jagiello's sole surviving child. In 1417, Jagiello married Elisabeth of Pilica, and in 1422, Sophia of Halshany. Hedwig was raised by both stepmothers. Proposed marriages Until the birth of Jagiello's son Władysław III in 1424, Hedwig's marriage was of paramount importance in Polish politics as her husband would presumably become King of Poland after Jagiello's death. The first known negotiations for her marriage occurred in 1419 between Jagiello and Eric, King of Sweden, Norway, and Dermark. The rulers met in Czerwińsk nad Wisłą to discuss an alliance against the Teutonic Knights. Eric proposed to marry Hedwig to his cousin and presumptive heir Bogislaw IX, Duke of Pomerania, who at the time was eight or nine years old. However, the Polish–Scandinavian–Pomeranian alliance did not materialize. On 12 April 1421, Hedwig was betrothed to Frederick II, Margrave of Brandenburg, second son of Frederick I, Elector of Brandenburg, who sought Polish alliance in the long-standing Brandenburg–Pomeranian conflict. According to the terms of the agreement, the marriage would take place when Frederick II reached age 14 in