 Sigismund, who took over the reign after his father's death in 1548, overcame the resistance and had Barbara crowned in 1550; a few months later the new queen died.Bona, estranged from her son returned to Italy in 1556, where she died soon afterwards.The Sejm, until 1573 summoned by the king at his discretion (for example when he needed funds to wage a war), composed of the two chambers presided over by the monarch, became in the course of the 16th century the main organ of the state power.