He was King of Sweden and Poland, but there were other Swedes who thought they could do a better job of it. They were probably right. Duke Karl (Karl IX) of Södermanland was one of them. He was a brutal, ruthless sort of fellow, but had good economic sense. Karl founded Göteborg, and planned to use it as a shipping port in order to get out of paying Danish tariffs. The Danes thought this was a bad idea and burned Göteborg to the ground. After that Karl turned his attention to removing Sigismund from the throne.
He held a meeting with his former enemies in Uppsala. They all wanted Sweden to be Lutheran, and Sigismund was Catholic, but nothing much came of their decision. The nobility feared Karl would become a despotic king with no respect for their high rank.
Things finally came to a head at Stångebro in 1598 – another war over religion. Will they never end? I mean, really. Thousands were killed. Sigismund was captured, but allowed to go back to Poland. The dog probably went with him.
Karl IX set to work as soon as Sigismund was gone. He gleefully executed his enemies in Stockholm after announcing that Sigismund had been deposed. He summoned a new Riksdag in Linköping. Several councilors were beheaded in the town square at what came to be known as the Linköping Bloodbath. Swedes were very into bloodbaths in those days. Karl was crowned King of Sweden in Uppsala in 1607, then went north to Finland to try an open up another seaport. He had a thing about seaports and once again his predilection started a war with the Danes. He defeated them at Stångebro, but then another war was started, this time between Sweden and Poland.
Karl did pretty well at first, and made his way into Livorna, but then the Poles counter attacked.
Karl’s army was defeated and he tried to get back to Sweden by crossing the Gulf of Finland, but the sea had started freezing over. His boat sank and he and his family almost went with it, but they made it to land and spent Christmas at Åbo castle. After that they took a long and very uncomfortable sleigh ride back to Stockholm.
As soon as Karl got over his sleigh-lag he assembled a new army made up of Swedes and mercenaries from Germany, France and England. He then led them to Livonia where they were totally destroyed. The survivors ran back to Sweden as fast as they could, and an armistice with Poland was signed in 1611.
Main while, in Russia, Ivan the Terrible had died. Pretenders to the throne started showing up, and bands of Cossacks began to plunder and ravage (an old Viking tradition) until a Swedish army led by Jakob De La Gardie liberated Moscow and installed Vassily Shuisky, as tzar.
De La Gardie had been held prisoner in Poland for four years as a young adult and after his release served under the Dutch general, Maurice of Nassau. He was Impressed with the Dutch way of waging war and introduced Dutch methods into the Swedish army upon his return to the service of Sweden.
De la Gardie’s victory in Russia was short lived. He was forced out of Moscow when Poland stormed into Russia with their own candidate, Sigismund’s son, Vladislav. Vladislav became the new tzar, but not for long.