Westerland was once the north-westernmost province of the Empire. Most of the trade with Bretonnia, as well as with more distant nations, flowed through its port city of Marienburg. A rich merchant class grew up in Marienburg, and the city came to be dominated by commoners who had grown wealthy through trade, adopting a republican form of local government at a time when this was still rare elsewhere in the Empire.

During the time of the Three Emperors, with imperial authority weak, the burghers of Marienburg saw their opportunity to mske their effective power constitutional. They found, in the person of Countess Magritta of Westerland, a noblewoman willing to accede to their claims for greater civil rights for commoners, and launched a campaign of bribery amongst those electors still participating in Imperial elections. They were successful beyond their dreams, and Magritta was elected Empress in 1979.

The Grand Theogonist of Sigmar, horrified by the threat this posed to Imperial power, declared the election illegitimate on the grounds that no woman could ascend to the throne of Sigmar, and this proved to be the last Imperial election for more than 300 years. Eventually, the Empire was reunified under Magnus the Pious, but Marienburg was brought back into the fold only reluctantly, remembering their humiliation, and valuing their own commercial talents over the pretensions of the noble class.

After a long negotiation, the weak and vaccillating emperor Dieter IV agreed to the secession of Westerland from the Empire. This led to his near immediate deposition as Emperor and the accession of the house of Holstein-Schliestein. Nevertheless, subsequent emperors were never able to reimpose control over Marienburg, and they settled into a position of tolerating, without formally recognising, the independence of Westerland - now referred to derogatrily by Imperial loyalists as the Wasteland. The Counts of Nordland still claim Westerland as part of their legal inheritance, but Marienburg law prescibes death for any Count of Nordland who steps foot in the city, and no Count has made any overt move to enforce their claim in a century.

Marienburg remains a wealthy city, serving as a point of transit for goods from across the Old World, and even distant lands such as Ulthuan and the New World. The city is home to one of the largest Elven communities of any human city, responsible for managing trade with Elven lands.

Marienburg has a republican government dominated by the wealthy merchant classes. A Staadtholder is elected on an annual basis from one of the ten great noble families, who fulfills the functions of a monarch and handles most diplomatic relations with foreign countries.