King of the Wends

One poetic explanation of the title was kingship over the antique people of the Vandals (vandalorum rex), but that idea came only in the 16th century.

A recent interpretation, not much supported in academic research, has been made that the part "Vend" in the later established titles of the kings of Sweden (three kingdoms: King of the Svear, Götar and Vends; Swedish: Svears, Göters och Venders konung) means Finland, the form presumably being akin to winds, "vind".

In Germanic languages, the name was Wends, and in medieval documentation the Latin name was sclavorum rex, referring to the Slavic peoples in and around the region now known as Mecklenburg.

Monarchs of Denmark bore the title for eight centuries, after it was first adopted by King Canute VI (reigned 1182 to 1202), who conquered the lands of the Wends in Pomerania and Mecklenburg.

When Sweden had made its final breakaway from the Kalmar Union that united it with Norway and Denmark, tensions between the two rulers were high, and it showed also in their flags, coat-of-arms and titles.