1260 when the island was seized by Prince Järmer of Rügen. The Germans gained rights to establish a trading outpost at Brøndhøj. A Norwegian, Alf Ellingsen, was also attracted by the island, defeating a defending fleet of 30 vessels to raid Møn and other islands during the reign of Erik Glipping (1259–1286). Glipping granted Stege a town charter, granting it sole rights to trade and tax certain commodities, which existed until 1857.
From the middle of the 12th to the mid-17th century Møn became a Danish crown property and was managed by a feudal lord. Its relative importance meant that appointments were made from the ranks of highest Danish nobility. The lord had responsibility for maintaining order and collecting taxes, hosting visits from royalty and important guests, and judging legal disputes. As a royal possession, the island was used as surety against loans made to the crown, and passed into various hands while debts remained unpaid. This gave the pledge holders the right to extract whatever revenue they could from the island while it remained pledged as security. Prince Witslav of Rügen held the island for 20 years from 1286, resulting in rebellions against him and further Norwegian raids
Herring fisheries, prosperity and decline
The island, and Stege in particular, prospered in the 14th century from the results of herring fishing, reaching the height of its wealth around 1500. It adopted a coat of arms including three herrings, and the town defences were strengthened. Around 1430 a rampart, wall and moat were created around the town by Eric VII. Three towers were created at each of the main approach roads, of which only Møllerporten still survives. However, the fortifications were no defence against fire, which at one point destroyed the greater part of the town, or against the plague.
In 1447, King Christopher III granted the town rights to trade outside Møn, within the remainder of Denmark. In 1450, Christian
