Vasa (vä´zə), Pol. Waza, royal dynasty of Sweden (1523–1654) and Poland (1587–1668). Gustavus I, founder of the dynasty in Sweden, was succeeded by his sons Eric XIV (reigned 1560–68) and John III (reigned 1568–92). John III married the sister of Sigismund II of Poland, and their son was elected (1587) king of Poland as Sigismund III. On John's death Sigismund succeeded to the Swedish throne, but his Catholicism led to his deposition (1599) in Sweden, where his uncle Charles IX (reigned 1604–11) succeeded him. The house was thus split into a senior Catholic line (in Poland) and a cadet Protestant line (in Sweden), and the two lines engaged in chronic warfare. Charles IX of Sweden was succeeded by Gustavus II; on Gustavus's death (1632) his daughter Christina ascended the throne. With Christina's abdication (1654) in favor of her first cousin, Charles X, the Swedish throne passed to the Zweibrücken line of the house of Wittelsbach. In Poland, Sigismund III was succeeded (1632) by his son Ladislaus IV, who was succeeded (1648) by his brother John II. John abdicated in 1668.