Go to the King's Island by speaking to A Sailor located in the tavern at the Silversky port (1480,2265,0), tell him: King then yes.
Then head to Chamberlain Thomas, who is exiled on the King's Island as well (2215,2480,0) and tell him: interview, quest, then yes.
You now need to kill 10 wandering mages (in less than 30 minutes).
Return once again to Chamberlain Thomas on the King's Island and tell him: quest, then interview.