Napoleon gives to his brother Jérôme the Kingdom of Westphalia, created by merging territories ceded by the Kingdom of Prussia in the Peace of Tilsit, among them the Duchy of Magdeburg, the Brunswick-Luneburgian territories of Hanover and Wolfenbüttel, and the Electorate of Hesse.
The latter's capital Kassel then fulfills the same function for Westphalia, and the king keeps court at the palace of Wilhelmshöhe, renamed Napoleonshöhe.
The state is a member of the Confederation of the Rhine.
Intended as a Napoleonic "model state", a constitution is written and enacted by King Jérôme on December 7, 1807, the day after he had arrived in Kassel, making Westphalia the first monarchy in Germany with a modern-style constitution.
The constitution makes all male residents citizens of equal rights.
Thus serfs are liberated and Jews emancipated, and soccage—one of the feudal duties and hence land tenure forms in the feudal system—is abolished.
The Napoleonic code is enacted, doing away with guilds and providing for the right of free enterprise.
A metric system of weights and measures is introduced.
Just as before the conquest, freedom of expression remains curtailed and censorship is instituted.
