The Duchy of Schleswig (Danish: Hertugdømmet Slesvig; German: Herzogtum Schleswig; Low German: Hartogdom Sleswig; North Frisian: Härtochduum Slaswik) was a duchy in Southern Jutland (Sønderjylland) covering the area between about 60 km (35 miles) north and 70 km (45 mi) south of the current border between Germany and Denmark. The territory has been divided between the two countries since 1920, with Northern Schleswig in Denmark and Southern Schleswig in Germany. The region is also called Sleswick in English.
https://en.wikipedia.org/wiki/Duchy_of_Schleswig
The Duchy of Schleswig (Danish: Hertugdømmet Slesvig; German: Herzogtum Schleswig; Low German: Hartogdom Sleswig; North Frisian: Härtochduum Slaswik) was a duchy in Southern Jutland (Sønderjylland) covering the area between about 60 km (35 miles) north and 70 km (45 mi) south of the current border between Germany and Denmark. The territory has been divided between the two countries since 1920, with Northern Schleswig in Denmark and Southern Schleswig in Germany. The region is also called Sleswick in English.
