Vilhelm Moberg
A History of the Swedish People, Part 1, PSU DL 648 .M62 1972
Violent, starving, perhaps half a million people plagued by a harsh environment, war and warlords.
The last chapter, Scandinavia's Greatest Monarch, describes Queen Margareta (Margaretha Valdemarsdotter) of Denmark, who assembles the defensive Kalmar Union (1.5 million people) out of Denmark, Norway, Sweden, and Swedish Finland in 1397, for decades of internal peace, and protection from Geerman Hanseatic and Holstein invasion and attack. Moberg notes that had the Union survived to the present day, the Wehrmacht might not have invaded Denmark and Norway.