1920 Schleswig plebiscites

Map of Schleswig / South Jutland before the plebiscites.

The Schleswig Plebiscites were two plebiscites, organized according to section XII, articles 109 to 114 of the Treaty of Versailles of June 28, 1919, in order to determine the future border between Denmark and Germany through the former duchy of Schleswig. The process was monitored by a commission with representatives from France, the United Kingdom, Norway and Sweden.

The Danish-ruled Duchy of Schleswig had been conquered by Prussia and Austria in the 1864 Second War of Schleswig along with the Danish-ruled German provinces of Holstein and Lauenburg. Article 5 of the Austro-Prussian Peace of Prague stipulated that a plebiscite should be held within 6 years to give the people of the northern part of Schleswig the possibility of voting between staying German or separating parts of Schleswig and repartitioning them to Denmark, an arrangement already denied by Denmark after the war of 1848 and again after the war of 1864, and then dropped completely in 1878 in the Treaty of Gastein between Austria and Imperial Germany. The border was respected later by both Denmark and Germany in the Optant Treaty of Copenhagen 1907. After the defeat of Germany in World War I Germany was forced to accept a plebiscite whose unilateral conditions then were defined by Denmark.

The plebiscites were held in two zones that were defined by Denmark. according to the ideas of the Danish historian Hans Victor Clausen Zone I was dimensioned as far towards the South as possible, therefore changing the Clausen-Line southerly from Tondern instead of northerly, and had to vote en bloc, all of it to one country or another, while, in the following smaller Zone II, each municipality was to decide its own allegiance, allowing Denmark to gain further territory and put the frontier farther southward according to eventual majorities in northern municipalities .

The first plebiscite was held in Zone I, the later Northern Schleswig on February 10, 1920. There, 74.9% (75,431 votes) of the public voted to come under Danish rule, 25.1% (25,329 votes) to stay German, but in three of the four major towns, especially in the southern region directly at the frontier to Zone II German majorities existed, especially a large German majority between 70% and 80% in and around Tønder and Højer. It was mostly this area that caused discussions after the voting, especially as this area had been regarded also by Clausen to be south of an imaginary German-Danish border.

Central Schleswig (Zone II) voted on March 14, 1920. 80.2% (51,742 votes) fell to Germany, 19.8% (12,800) to Denmark. Since a Danish majority in this zone was produced in only three small villages on the island of Föhr, none of which were aligned with the coming border, the Commission Internationale de Surveillance du Plébiscite au Slesvig decided on a line almost identical to the border between the two zones. The poor result for Denmark in Central Schleswig, particularly in Flensburg, Schleswig's largest city, triggered Denmark's 1920 Easter Crisis.

A plebiscite was not held in the southernmost third of the province (Zone III) as the population was almost all pro-German.

Selected results in detail:

Electorate	German name	Danish name	For Germany		For Denmark
			percent	votes	percent	votes
Zone I (Northern Schleswig), 10 February 1920			25.1 %	25,329	74.9 %	75,431
District of	Hadersleben	Haderslev	16.0%	6,585	84.0%	34,653
Town of	Hadersleben	Haderslev	38.6%	3,275	61.4%	5,209
District of	Apenrade	Aabenraa	32.3%	6,030	67.7%	12,653
Town of	Apenrade	Aabenraa	55.1%	2,725	44.9%	2,224
District of	Sonderburg	Sønderborg	22.9%	5,083	77.1%	17,100
Town of	Sonderburg	Sønderborg	56.2%	2,601	43.8 %	2,029
Town of	Augustenburg	Augustenborg	48.0%	236	52.0%	256
Northern part of District of	Tondern	Tønder	40.9%	7,083	59.1%	10,223
Town of	Tondern	Tønder	76.5%	2,448	23.5%	750
Town of	Hoyer	Højer	72.6%	581	27.4%	219
Town of	Lügumkloster	Løgumkloster	48.8%	516	51.2%	542
Northern part of District of	Flensburg	Flensborg	40.6%	548	59.4%	802
Zone II (Central Schleswig), 14 March 1920			80.2 %	51,742	19.8 %	12,800
Southern part of District of	Tondern	Tønder	87.9%	17,283	12.1%	2,376
Southern part of District of	Flensburg	Flensborg	82.6%	6,688	17.4%	1,405
Town of	Flensburg	Flensborg	75.2%	27,081	24.8%	8,944
Northern part of District of	Husum	Husum	90.0%	672	10.0%	75

Results of the plebiscite.

Directly after the announcement of the results from Zone I, an alternative draft for the frontier was made by the German administrator Johannes Tiedje. The proposed frontier would have incorporated Tondern, Hoyer, Tingleff and neighbouring areas and also some parts north from Flensburg – the so-called Tiedje Belt – and would have created almost equal minorities on both sides of the frontier instead of 30,000 to 35,000 Germans in Denmark and 6,000 to 8,000 Danes in Germany.

This and suggestions like this were not accepted and so Northern Schleswig was surrendered to Denmark on 15 June 1920, and the territory was officially named the South Jutlandic districts, more commonly Southern Jutland, although this name is historically identical to the whole of Schleswig.

See also

• Easter Crisis of 1920
• Schleswig-Holstein Question
• Danish minority in Southern Schleswig
• North Schleswig Germans
• History of Schleswig-Holstein
• Southern Schleswig
• Danish constitutional referendum, 1920