House of Vasa

The House of Vasa (Swedish: Vasaätten, Polish: Wazowie) was an early modern royal house founded in 1523 in Sweden, ruling Sweden 1523–1654, the Polish-Lithuanian Commonwealth 1587–1668 and the Tsardom of Russia 1610–1613 (titular until 1634). Its agnatic line became extinct in Poland with the death of King John II Casimir of Poland in 1672.

The House of Vasa descended from a Swedish 14th century noble family, tracing agnatic kinship to Nils Kettilsson (Vasa) (died 1378), Vogt of the castle Three Crowns in Stockholm. Several members held high office during the 15th century. In 1523, after the abolisment of the Kalmar Union, Gustav Eriksson (Vasa) became King Gustav I of Sweden and the royal house was founded. His reign is sometimes referred to as the beginning of the modern state of Sweden, along with the foundation of the Protestant Church of Sweden during the Protestant reformation as a result of the King's break with the Roman Catholic Church, usurpring its property on Swedish soil. Yet, his son, King John III of Sweden, married a Catholic Polish Queen Catherine Jagiellon, eventually spreading the House of Vasa to Poland.