Søren Norby, selfstyled as Severin Norbi was a Danish leading naval officer in the fleets of Danish kings Hans I and Christian II. He commandeered the greatest ship of the Danish fleet in naval wars against Sweden and Lübeck. Norby governed various land possessions in Scandinavia, ruling Gotland from 1517 to 1525. His rebellion against Frederick I of Denmark in 1525 was defeated, and he fled Denmark, ending his life in the employ of Charles V, Holy Roman Emperor.

Christian II was a Scandinavian monarch under the Kalmar Union who reigned as King of Denmark and Norway, from 1513 until 1523, and Sweden from 1520 until 1521. From 1513 to 1523, he was concurrently Duke of Schleswig and Holstein in joint rule with his uncle Frederick.