The building block of the republic was the Kirchspiel, the parish. By the 14th century the marshland villages had knitted themselves into a federation of self-governing parishes. Real power, though, ran through the Geschlechter - extended kin groups whose leading families supplied the men who judged, negotiated and, when required, fought. In 1447 the arrangement was finally written down. The Dithmarscher Landrecht established a high court staffed by forty-eight judges appointed for life, and the Achtundvierziger, the Forty-Eight, soon became far more than a bench. They were the executive of an emerging peasant state: they made law, they handled foreign policy, and in 1533 they would reorganise the church. A reformed version of that law code, issued in 1567, was still in force into the 19th century.

If you want to understand Dithmarschen, count the castles. There are none worth the name; the few ever built played minor roles and are long since reduced to groundworks. Churches carried the weight instead, spiritual and worldly at once. St John the Baptist in Meldorf, so large that people call it the Meldorf Cathedral, was the only church in Dithmarschen between the 9th and 11th centuries and one of the few anywhere north of the Elbe. Through the Middle Ages it was where the representatives of the political parishes met. Its Gothic interior, dating from roughly 1250 to 1300, carries paintings counted among the finest in Schleswig-Holstein - a plain measure of how rich these farmers actually were. Later the centre of gravity shifted north. From 1447 the northern Ditmarsians gathered auf der Heide, on the heath, and the Forty-Eight took to meeting in St Jurgen's church at Heide. Political and religious life here stayed undivided until Prussia absorbed Schleswig-Holstein in 1867.

The emperor recognised Dithmarschen as an imperial fief and summoned its peasants to send representatives to royal assemblies and to the Imperial Diet - an extraordinary status for men who worked their own fields. Neighbouring princes kept testing it, and kept failing. Gerhard III was thrown back at Wohrden in 1319. Albert II, Count of Holstein-Rendsburg, launched his own attempt in 1403 and died of his injuries during the campaign. Unable to win in the field, Holstein tried the courts, and lost the legal battle of 1474 to 1481 as well. The republic played the commercial game with equal skill. In 1468 it allied with Lubeck to protect shared trading interests and slow the spread of feudalism, and on the strength of those Hanseatic privileges Ditmarsian merchants shipped to Livonia and other Baltic ports through the 15th century. The most famous test came on 17 February 1500, when an outnumbered Ditmarsian force under Wulf Isebrand destroyed a Danish invasion army at Hemmingstedt.

The Reformation arrived violently. Early Protestant preaching met fierce resistance, and Henry of Zutphen was killed in December 1524; within a decade the mood had reversed, and in 1533 the Forty-Eight simply converted the Ditmarsian church into a Lutheran state church of their own. What ended the republic was not doctrine but arms. In 1559, in the Last Feud, an invasion commanded by Count Johan Rantzau broke the peasants' resistance and forced them to surrender their political and religious independence. The conquerors divided the spoils, the south passing to Holstein in personal union with Denmark and the north to the other Duke of Holstein. Even in defeat, though, the Ditmarsians extracted terms: the Danes were obliged to leave the district with a considerable degree of self-government. The bitterness outlasted the fighting: the district coat of arms shows a Holstein knight, and for centuries people here refused it as the badge of conquerors; only in 1930, the old hostilities finally cold, was it taken up again.

The republic's independence rested on something physical: land the Ditmarsians had made themselves. Since roughly the 8th century people here have lived on warfts, artificial mounds raised above the reach of storm tides. Dike building began in the 12th century, and from the 15th the marshes were pushed seaward until reclamation had nearly doubled the district's size. The resulting soil is among the most fertile in Germany, and Dithmarschen's vegetable farms still return the highest yields in Schleswig-Holstein. The land stays stubbornly horizontal - the high point near Schrum reaches 78 metres, while near Burg the ground sits half a metre below sea level. That flatness and the North Sea wind made this the birthplace of German wind power. The experimental GROWIAN turbine stood at Kaiser-Wilhelm-Koog from 1983 to 1987, and Germany's first wind park opened on the same coast in 1987. Today around 800 turbines turn over these fields - five percent of every wind turbine in Germany, standing on 0.15 percent of its area.