That bit her several times, too. Duchies were power vehicles until the new estate system. Now you can reward ambitious rivals with a Margravate, and keep the appointment authority of the Duke with yourself or another. <3
But that's exactly why its a balancing act as a Ruler, and why its really an interesting dynamic.
Not to mention it was incredibly smart for her to get rid of me as her Judge, through a legitimate reason. At the time, I had too much support from the nobility.