After a century of happy obscurity Denmark re-entered world history with Waldemar I (1157–82). Helped by his minister Absalon, Archbishop of Lund, he organized a strong government, cleared his seas of pirates, and enriched Denmark by protecting and encouraging trade. In 1167 Absalon founded Copenhagen as a “market haven”—Kjoebenhavn. Waldemar II (1202–41) replied to German aggression by conquering Holstein, Hamburg, and Germany northeast of the Elbe. “For the honor of the Blessed Virgin” he undertook three “crusades” against the Baltic Slavs, captured northern Estonia, and founded Reval. In one of these campaigns he was attacked in his camp, and escaped death, we are told, partly by his own valor, partly through the timely descent, from heaven, of a red banner bearing a white cross; this Dannebrog, or Dane’s Cloth, became thereafter the battle standard of the Danes. In 1223 he was taken prisoner by Count Henry of Schwerin, and was released, after two and a half years, only on his surrendering to the Germans all his Germanic and Slav conquests except Rügen. He devoted the remainder of his remarkable life to internal reforms and the codification of Danish law. At his death Denmark was double its present area, included southern Sweden, and had a population equal to that of Sweden (300,000) and Norway (200,000) combined. The power of the kings declined after Waldemar II, and in 1282 the nobles secured from Eric Glipping a charter recognizing their assembly, the Danehof, as a national parliament.
Only the imaginative empathy of a great novelist could make us visualize the achievement of Scandinavia in these early centuries—the heroic conquest, day by day, foot by foot, of a difficult and dangerous peninsula. Life was still primitive; hunting and fishing, as well as agriculture, were primary sources of sustenance; vast forests had to be cleared, wild animals had to be brought under control, waters had to be channeled to productive courses, harbors had to be built, men had to harden themselves to cope with a nature that seemed to resent the intrusion of man. Cistercian monks played a noble role in this agelong war, cutting timber, tilling the soil, and teaching the peasants improved methods of agriculture. One of the many heroes of the war was Earl Birger, who served Sweden as prime minister from 1248 to 1266, abolished serfdom, established the reign of law, founded Stockholm (c. 1255), and inaugurated the Folkung dynasty (1250–1365) by putting his son Waldemar on the throne. Bergen grew rich as the outlet of Norway’s trade, and Visby, on the island of Gotland, became the center of contact between Sweden and the Hanseatic League. Excellent churches were built, cathedral and monastic schools multiplied, poets strummed their lays; and Iceland, far off in the Arctic mists, became in the thirteenth century the most active literary center in the Scandinavian world.