Holstein was a powerful principality in the north of Germany. It lay on the border of Denmark. During the Middle Ages, several wars were fought between Denmark and Holstein. Holstein had powerful counts and a well-equipped army. The county was established in 1111 as a part of the Roman-German Empire. In the beginning of the 13th century, Holstein was conquered by Denmark. A few decades later however, it became an independent county once again.
Holstein was at its strongest during the 14th century. The counts John III and Gerhard III had actual power over Denmark in the 1330 ´s. They controlled large parts of Denmark, including Skåne and Blekinge. When these counts ruled, Denmark had no King. The people of Skåne were not pleased with the German counts. They asked the Swedish King, King Magnus Eriksson, to buy Skåne and Blekinge which he did, in cash. In the 1360 ´s, another German count, Count Henry of Holstein, was the Bailiff at Kalmar Castle.
Holstein ´s powerful position was annoying to the neighbouring countries and Holstein was often at war. King Erik of Pommern fought a hard battle with Holstein at the beginning of the 15th century.