Complex sentence: In 1520, the city of Stockholm was sieged and taken by the Danes after the defeat of Christina Gyllenstierna, but the rest of Sweden soon rose in rebellion and in 1522, the city was now besieged by the Swedes under Gustav Vasa.
Split into simpler sentences: In 1520, the city of Stockholm was sieged and taken by the Danes after the defeat of Christina Gyllenstierna. Soon after, however, the rest of Sweden rose in rebellion and in 1522, the city was besieged by the Swedes under Gustav Vasa.