At the death of John in 1592, his son Sigismund succeeded him. Sigismund was already ruler of the Polish–Lithuanian Commonwealth, through his mother, and he would rule Poland from 1587 to 1632. He set up a regency and continued to reside in Poland. On learning about the Uppsala Synod, that finally declared Sweden's Lutheran doctrines, he returned home to protest. He found that the Riksdag of the Estates had already dethroned him and replaced him by Gustav Vasa's youngest son, his uncle, Charles IX. A brief civil war ensued that Sigismund lost in 1598, where after he fled the country never to return.