Archduchy of the River

Most of the previously autonomous towns and cities on both the western and eastern banks of the Great River were placed under direct imperial control in the fifth century of the New Empire. In 604, Emperor Otto VI created the Archduchy of the River as a position for his third (and favourite) son, Hennik. Since then, the title of Archduke of the River has been given by the Emperor to a favoured close relative. It is a very lucrative position.
The current Archduke is Manfred, the son of Emperor Otto IX .
When a new Emperor is elected, he will appoint a new Archduke. By tradition, the outgoing Archduke is made a Grand Duke / Grand Duchess as an honorary title (i.e. without a fief).