Dithmarschen (German pronunciation: [ˈdɪtmaʁʃn̩] ⓘ, Low Saxon: [ˈdɪtmaːʃn̩]; archaic English: Ditmarsh; Danish: Ditmarsken; Medieval Latin: Tedmarsgo) is a district in Schleswig-Holstein, Germany.

Today it forms a kind of artificial island, surrounded by the Eider river in the north and the Kiel Canal in both the east and southeast.

After 1180 Prince-Archbishop Siegfried ceded Dithmarschen, which was supposed to belong to his Prince-Archbishopric of Bremen, to his brother Bernhard III, Duke of the younger Duchy of Saxony.

In his new position of Duke of Saxony he held the Land of Hadeln, opposite of Dithmarschen on the southern bank of the river Elbe.

Adolf III of Schauenburg, Count of Holstein, at enmity with the Ascanians, had de facto taken a loose possession of Dithmarschen.

He persuaded Adolf III to waive his claim to Dithmarschen, in return for being paid regular dues to be levied from the Ditmarsians after subjugation.

Hartwig, owing dues to Adolf III and the soldiers' pay to Maurice I, was trapped and could not afford to wage a second war.

Though several times neighbouring princely rulers, accompanied by their knights and mercenaries, attempted to subjugate the independent peasants to feudalism, they were unsuccessful.

After Eric IV, Duke of Saxe-Lauenburg had raided Dithmarschen, the Ditmarsians blamed his son-in-law, Albert II, Count of Holstein-Rendsburg, for complicity, who then used this as a pretext for his own unsuccessful conquest attempt in 1403, dying during the campaign from inflicted injuries.

[2] Based on the Hanseatic obligations and privileges from the pact signed with Lübeck, Ditmarsians had established trade with Livonia and neighbouring Baltic destinations in the 15th century.

[6] In April 1499 Count John XIV of Oldenburg invaded the Weser and North Sea marshes of Stadland and Butjadingen, both of which the Prince-Archbishopric of Bremen claimed overlordship over, in order to subject their free peasants.

[5] Conversely, John V and his son Magnus of Saxe-Lauenburg had already allied with Henry IV the Elder of Brunswick and Lunenburg, Prince of Wolfenbüttel, on 24 November 1498, to conquer Wursten.

[4][5] Henry IV obliged to send 3,000 landsknechts, who should gain their payment by ravaging and plundering the free peasants of Wursten, once successfully subjugated.

[8] The allied forces, with the Ditmarsians invading by crossing the Elbe, easily conquered the Land of Hadeln, and defeated Magnus.

By 20 November 1499 Magnus hired the so-called Black Guard [de] of 6,000 ruthless and violent mostly Dutch and East Frisian mercenaries, commanded by Thomas Slentz, prior operating in the County of Oldenburg.

[4][8] The Black Guard invaded the Prince-Archbishopric of Bremen, passing through and ravaging areas in the Prince-Bishopric of Verden and the Brunswick-Lunenburgian Principality of Lunenburg-Celle, leaving behind a wake of devastation in the countryside and especially in the looted monasteries.

[13][14] So the Guard turned northeastwards, looting Neuenwalde Nunnery underways, into Hadeln, repressing the joint forces of Rode and the cities – lacking support by Bremian knights and the Ditmarsians –, recapturing it for Magnus in early 1500.

[14] Magnus, unable to pay the mercenaries so that they turned even the more oppressive for the local population, was like the Sorcerer's Apprentice, who could not get rid of "the spirits that he called".

By mid-January 1500 King John of Denmark hired the Guard and guaranteed for its safe conduct first southeastwards via Lunenburg-Cellean Winsen upon Luhe and Hoopte, crossing the Elbe by Zollenspieker Ferry to the Hamburg-Lübeckian bi-urban condominium (Beiderstädtischer Besitz) of Bergedorf and Vierlande.

On 17 February 1500, in the Battle of Hemmingstedt, the outnumbered Ditmarsians, led by Wulf Isebrand, defeated the invading armies and thus destroyed King John's dream of subjecting Dithmarschen.

After violently repelling the first preaching of proponents of the Reformation, slaying Henry of Zutphen in December 1524, Lutheranism nevertheless started to win over Ditmarsians.

[2] Thus Ditmarsian merchants, along with those from Teutonic Prussia, were the only beneficiaries of a quasi membership within the Hanse, although lacking the background of citizenship in an autonomous or free city.

[2] It was not until 1559 and the Last Feud between the King of Denmark and the Ditmarsians that the free peasants were forced to give up their political and religious autonomy by the successful invasion commanded by Count Johan Rantzau from Steinburg, one of the best strategists of the time [citation needed].

Two years later, following the Austro-Prussian War, Dithmarschen became part of the Kingdom of Prussia, which annexed Holstein and Schleswig making them subsequently the Province of Schleswig-Holstein.

The Middle Ages in Dithmarschen are held to have continued into the 19th century, when the Kiel Canal was completed, fens began to be drained, and agricultural reforms took place.

The people of northern Dithmarschen began to meet in 1447 "auf der Heide" ("on the heath"); later, the Council of the 48—representatives of the most important families and the central decision body of Dithmarschen—met at St. Jürgen.

Recent competition with the former Warsaw Pact states and their Baltic coasts has had less impact on Dithmarschen because their coastal formations are quite different.

Fitness and health play an increasing role in German life, so tracks and roads for bicycles and inline skates are being built.

After Schleswig-Holstein was annexed by Prussia in 1867, some villages became towns and therefore administratively left their old parishes: Meldorf in 1869, Heide in 1878, Marne in 1891, and Wesselburen in 1899.

The two most important towns, Heide and Meldorf, were built on the safe geest but directly adjacent to marshland where people could have their fields.