In 1325, the Teutonic Knights built a castle called 'Yladia' or 'Ilaw', later known as 'Preussisch Eylau', in the center of the Old Prussian region Natangia. Ylow is the Old Prussian term for mud or swamp. The settlement nearby developed slowly, but in 1348 the Teutonic Order gave the privilege to establish twelve pubs at the surrounding area of the castle. Even though the village had only a few inhabitants, due to its central position it was often used as meeting place for different officials of the Order. In 1427 e.g. the Eylau County Law (Eylauer Landesordnung) was published by the Order.
Throughout the Thirteen Years' War the castle was besieged on May 24, 1455 by troops of the Prussian Confederation under the command of Remschel von Krixen, but the garrison defeated these troops. Also throughout the Horsemen's War in 1520 the castle was unsuccessfully besieged by troops of the Polish Kingdom, which caused a devastation of the village itself.References:
The Externsteine (Extern stones) is a distinctive sandstone rock formation located in the Teutoburg Forest, near the town of Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. Archaeological excavations have yielded some Upper Paleolithic stone tools dating to about 10,700 BC from 9,600 BC.
In a popular tradition going back to an idea proposed to Hermann Hamelmann in 1564, the Externsteine are identified as a sacred site of the pagan Saxons, and the location of the Irminsul (sacral pillar-like object in German paganism) idol reportedly destroyed by Charlemagne; there is however no archaeological evidence that would confirm the site's use during the relevant period.
The stones were used as the site of a hermitage in the Middle Ages, and by at least the high medieval period were the site of a Christian chapel. The Externsteine relief is a medieval depiction of the Descent from the Cross. It remains controversial whether the site was already used for Christian worship in the 8th to early 10th centuries.
The Externsteine gained prominence when Völkisch and nationalistic scholars took an interest in the late 19th and early 20th centuries. This interest peaked under the Nazi regime, when the Externsteine became a focus of nazi propaganda. Today, they remain a popular tourist destination and also continue to attract Neo-Pagans and Neo-Nazis.