ENAfter the death of Ladislaus Jagiellon near Varna in 1444 only Queen Sophia of Halshany, a widow of Ladislaus Jagiellon, remained in the Crown. Her younger son Casimir resided at that time in Lithuania where he held the office of Grand Duke of Lithuania. The period of interregnum, which lasted until 1447 when Casimir decided to succeed to the throne, resulted in strengthening the relationship with his mother. During the reign of Casimir in the Kingdom of Poland Sophia was the most trusted confidante in the life of the king. It was she who welcomed him at the Polish-Lithuanian border and said goodbye when he was heading for Lithuania. When Casimir wedded Elisabeth of Austria, Sophia discreetly retreated from the life of a young marriage, staying, however, in a friendly relationship with her daughter-in-law. All her grandchildren were born in the presence of queen-mother. Casimir left her mother complete freedom, allowing her to singlehandedly administer her properties and even approved the appointment of the Starost, who Sophia selected during the period of interregnum. After his mother’s death, however, he deprived her properties of privileges and restricted the endowment for her former foundations.