Duke / Duchess

The first Royal Noble Title the title of Duke/Duchess is often awarded to the non-heir children of the King/Queen.  It may also be granted  to non-Royals who are very loyal to the Crown.
Landed Dukes are entitled to grant title to lesser nobles.
Royal Dukes are limited to 25 Knights and 250 Men-at-Arms.  They may not grant titles themselves but must petition the Crown.

Duties

The Duke and Duchess is to provide military, political, and economic support to the Crown.

Responsibilities

Landed Dukes/Duchess must  organize their duchy to collect taxes, administer the Crown's Justice, raise armies as the Crown needs, and defend the populace of their Duchy.

Type

Nobility, Hereditary

Reports directly to

King / Queen