Wow, this is fascinating. I’d never heard of the Hanseatic League before, it looks worth reading more about. I was wondering why the Hanseatic League was sponsoring hostilities against Florence (which I didn’t think would have much of a navy?) and I think this actually pictures an incident that took place during the Anglo-Hanseatic War by the privateer Paul Beneke:

In 1473 in the North Sea, [Beneke] followed and boarded the galley St. Matthew, which had a registered owner’s name of Tommaso Portinari, but was actually owned by England. It was bound for Italy. Beneke seized, amongst other items, Hans Memling’s triptych The Last Judgment. The painting had been commissioned for the chapel of a branch manager of the Medici Bank, Angelo Tani,[2] and included a head portrait of Portinari.

Not surprisingly, the owners objected to the seizure and the issue was taken up in the papal court. Danzig defended Beneke on the basis that the seizure was a legitimate act of war as the Hanseatic League was at war with England at the time. The painting was never returned. Instead, it was donated by three Danzig patricians, Sidinghusen, Balandt and Niederhof, to the St. George Brothers church in Danzig, whence it came to Danzig’s St. Mary’s Church. The Burgundian Duke, under whose flag the St. Thomas had run, brokered a peace between war-weary England and the Hanseatic League, restoring their trading rights.

https://en.wikipedia.org/wiki/Paul_Beneke

Note that the awning in the back bears the coat of arms of the Duke of Burgundy, and if you zoom in, you see that the painting being admired looks like the triptych The Last Judgment. As described above, this incident is significant because it led to the end of the war.