Søren Norby Søren Norby , selfstyled as Severin Norbi ( died 1530 ) 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 . Norby had two children with unknown women ; a son named Olov and a daughter , of whom little is known . Biography . Norby was of poor Funen nobility , probably born between the late 1460s and the early 1480s . The first mention of Norby is as a sailor for Swedish regent Svante Nilsson Sture during peace time in 1504 . In 1507 , he was a captain for Hans I of Denmark and pillaged Åland . Norby commandeered the largest ship of Hans ' fleet during the war against Sweden and Lübeck from 1507 to 1512 , and served alongside Jens Holgersen Ulfstand . In 1510 , Norby received a letter of marque from Hans , allowing him to commit piracy on all enemy vessels . For his success in the war , Norby was rewarded with Börringe Priory in Scania and also owned Haraldsborg near Roskilde . Under new King Christian II of Denmark , Norby was sent as leader of a fleet to aid Charles II of Burgundy against Geldern in 1514 . He was granted seignory of Iceland from 1515 to 1517 , and in 1517 he was granted Visborg on Gotland , which was made a life - time grant in exchange for Börringe Priory and Haraldsborg in 1518 . During Christian II ' s war to win the throne of Sweden against Lübeck and Sweden from 1517 to 1520 , Norby was the leader of the Danish fleet , and attacked both military and merchant vessels from his strategic position at Visborg . Norby was officially allowed to continue with piracy in 1518 . He captured , and was subsequently granted , Borgholm on Öland in 1519 , and his blockade of Stockholm helped Christian II secure the Swedish throne in 1520 . Norby helped make arrests during the Stockholm Bloodbath , but is said to have rescued many Swedes by sailing them out of Stockholm . He was then granted Kalmar Castle . Norby was tasked with finding a sea route to the West Indies via Greenland , but had to abandon his plans due to the rise of Gustav Vasa who was crowned King of Sweden in 1521 . In the following years , Norby lost his possession of Öland , but conquered Finland and Norrbotten . When Christian II abdicated under great pressure in April 1523 , Norby was the only seignory who stayed loyal to him . Norby lost Kalmar and Finland that year , and fortified himself at Visborg . He was isolated and began minting his own coins in order to pay his men , bearing the name insignia " Severin Norbi " . He negotiated with both the new Danish king Frederick I , Sweden , and Lübeck to keep his possession of Visborg . After diplomatic machinations , Norby eventually stayed at Visborg , and he launched a rebellion in Blekinge in April 1525 , in the name of Christian II . Frederick I ' s general Johan Rantzau defeated Norby , and he reached a settlement with Denmark , in which Norby exchanged Visborg for land in Blekinge . During the surrender of Visborg , Norby was double cross ed by Frederick I ' s advisor Otte Krumpen and left for capture by Lübeck . However , he was promptly released as his men rejected leaving Visborg without him , and they then resettled in Blekinge as agreed . While in Blekinge , Norby continued his piracy against Lübeck and Sweden , and carried on supporting Christian II against Frederick I . His three enemies finally united to attack him in August 1526 . Norby escaped to Livonia , and travelled to Vasili III of Russia in Moscow . With the help of King Ferdinand I of Bohemia , Norby travelled to Mechelen where he was reunited with Christian II around November 1528 . As Christian II ' s position was too weak to attempt a reconquest of Denmark , Norby travelled to join Charles II of Burgundy , now known as Charles V , Holy Roman Emperor , in 1529 . He wrote to Christian II of his partaking in the Siege of Florence in February 1530 , where he died shortly thereafter .