In 1595 the Riksdag of the Estates assembled at Söderköping (consequently sometimes known as the Riksdag of Söderköping) and elected Duke Charles IX of Sweden as regent of Sweden in place of his Catholic nephew Sigismund—though it did not formally depose Sigismund—because he had violated his agreement as king-elect and that of 1593 with the Uppsala Synod and had instead championed Catholic counter reformation measures, appointed catholics to high offices and established catholic schools during this religiously volatile era—all in violation of his agreement with the Synod in 1593. The renewed controversy came to a head in 1594, resulting in the Riksdag setting aside his authority, and the whole history of Sigismund with his claim on the Swedish throne became a succession of trigger events leading to the subsequent seven decades of dynastic warfare known as the Polish-Swedish wars. He was formally deposed by the Riksens ständer at Linköping, 24 February 1600, which declared he had abdicated his throne. The same Riksdag approved the execution of eight of Charles IX's opponents in the Swedish nobility as allies of King Sigismund (See Linköping Bloodbath).
Today Söderköping is mainly a tourist attraction visited by foregin tourists by boat on Göta Kanal and from people living in the region by car. This mix of people usually meet up in the central part of town for an icecream at the famous ice-restaurant Smultronstället. Many adventures gather in Söderköping as several climbingroutes are right in the city centre and the archipelago is just a few miles away.