King Władysław III , funded by Sophia in 1431–1432 On 1 June 1434 Jogaila died in
Horodok. The power was seized by Bishop
Zbigniew Oleśnicki and his supporters. On 25 July 1434, following the decisions of the Jedlnia congress, ten-year-old
Władysław III of Poland was crowned as the King of Poland. The regency was entrusted to the royal council, and not directly to either Sophia or Oleśnicki who continued to struggle for influence in the council. In the summer of 1435, Sophia helped
Iliaș of Moldavia, the husband of her youngest sister, escape a Polish prison and regain power in
Moldavia. Iliaș swore fealty to Władysław and Moldavia paid a tribute to Poland. She also supported a project to betroth Władysław and
Anne, Duchess of Luxembourg, who was at the time heiress to the
Kingdom of Hungary and
Bohemia. However, the project fell through. After the death of
Sigismund, Holy Roman Emperor,
Bohemian nobility, mainly
Hussites opposing
Albert of Austria, elected
Casimir IV Jagiellon as their king in March 1438 in
Chrudim. It is not known whether Sophia took any action to facilitate this election, but she was generally supportive of the Hussites while Oleśnicki strongly opposed them. In fall 1438, Polish army invaded Bohemia. However, the campaign was poorly organized and, after the defeat of Casimir's supporters in
Želenice, the army returned to Poland in October 1438. In December 1438, Polish nobles gathered in
Piotrków Trybunalski and proclaimed 14-year-old Władysław to have attained the age of majority. That officially dissolved the regency but did not strengthen Sophia's position against Oleśnicki. She actively took part in organizing a
confederation "for protection of the king and order in the kingdom," which opposed Oleśnicki and supported Hussites, in
Nowy Korczyn. The confederation, led by
Spytek of Melsztyn, was defeated in the
Battle of Grotniki. After the death of Albert in October 1439,
Hungarian nobles elected Władysław as their king. Sophia escorted Władysław to the Hungarian border. They said goodbye on 22 April 1440 in
Czorsztyn. It was the last time Sophia saw her eldest son. In March 1440,
Sigismund Kęstutaitis, Grand Duke of Lithuania, was murdered. With Władysław in Hungary,
Lithuanian nobles, led by
Jonas Goštautas, invited Casimir to
Vilnius and elected him as the Grand Duke. Sophia remained in Poland and devoted the next four years to the
Sanok Land and
Sanok Castle. Reportedly, she was a capable administrator and earned respect from local residents. However, income from the land did not support her royal lifestyle and she accumulated some debts.
King Casimir IV Władysław was killed in the
Battle of Varna on 10 November 1444. The news propelled Sophia back into national politics. In April 1445, she participated in the congress in
Sieradz where Polish nobles elected Casimir as their king. However, Casimir was not eager to claim the throne and refused to travel to Poland. Sophia travelled to Lithuania where she met Casimir, after a separation of five years, in
Hrodna in October 1445. Casimir refused to come to Poland and for the next two years, Sophia acted as an intermediary between Casimir and Polish nobles. In 1446, Polish nobles selected
Bolesław IV of Warsaw as their king if Casimir refused. Sophia once again sent envoys to her son who finally agreed to become the king. According to
Jan Długosz, Sophia's motherly pleas convinced nobles to confirm Casimir as their king in
Nowy Korczyn despite Oleśnicki's support to Bolesław. On 25 June 1447 Casimir was crowned King of Poland. As the new king, Casimir isolated Oleśnicki from power but allowed Sophia to participate in the royal council. She accompanied Casimir in his travels and continued to influence his decisions. Casimir supported Sophia's nephews,
Roman II and
Alexăndrel of Moldavia. Her influence decreased significantly after Casimir married
Elisabeth of Austria in 1454. Her last known political action was sending an envoy to newly elected
Pope Pius II to find out his opinions on the
Polish–Teutonic War (1454–66). According to Długosz, Sophia became ill after eating too many melons and refused treatment. The illness worsened and she was paralyzed. She died on 21 September 1461. She was buried in the Holy Trinity Chapel of the
Wawel Cathedral. She had funded the construction and decoration of the chapel in 1431–1432. At the time of her death, she had four grandsons and one granddaughter. Sophia sponsored a translation of the
Bible into the Polish language (1453–1461). Even though the translation was not completed, the work, known as
Bible of Queen Sophia, is an important monument of the Polish language. ==See also==