Talk to Ser Maximilian, outside the Gran Soren Castle Gates, and tell him that you wish to hear the Duke's directive. Note that this will CANCEL all previous Wyrm Hunt quests (any ones you have not started will no longer be available, and any of those quests in progress will be considered FAILED), and you will not be able to do them again. These include:

The Cypher
A Fortress Besieged
Seeking Salvation
The Watergod's Altar

it is recommended you do these first, so that you can get all the achievements. The above quests also have good loot to be found, as well as experience and rewards. We did a full walkthrough for each of those quests in the previous chapters, so you should have no problem completing them.

Ser Maximilian emphasizes again how your meeting with the Duke will put an end to any current tasks, and that you will be asked to return your license to the Wyrm Hunt. Confirm that you are prepared to see the Duke (or say "No" if you still want to complete other Wyrm Hunting quests). He will ask you yet again, to confirm that you don't need the Wyrm Hunt License anymore. Tell him you are sure. He instructs you to enter the castle.

This begins the quest:

Come to Court
Visit the Duke

Objective
Your feats in the Wyrm Hunt have earned you an audience with Duke Edmun himself. Perhaps he will offer missions of greater merit.

Details
Meet with His Grace in the castle's audience chamber.

Duke Edmun, leader of all Gransys, is often hailed as the "Dragon's Bane". Pawns are forbidden from entering the castle.

Enter the castle, and find yourself in the Duke's Demesne. Feel free to explore the area, there are some chests around, as well as crates with coin pouches in the observation rooms in the towers. There is also a door leading to a room containing a bunch of chests.

Enter the main audience room when you are ready. The court jester greets you and opens the door. Approach the throne. He knights you as a member of the Wyrm Hunt, telling you all the roads in Gransys will be open for you.

You now need to see to the royal orders. Explore the inside of the castle a bit, then step out back to the courtyard. Approach Aelinore, the Duke's wife, in the Duchess's Gardens. There will be another cutscene. Then, as you leave the castle, there is another cinematic. Ser Alvert tells you that you have been granted free passage into the castle, and that you will take your orders from the duke's chamberlain, Aldous Ludric Sorn, who is in charge of assigning royal orders.

This completes the quest, Come to Court