Where and for what purpose does Claudius send Cornelius and Voltemand?

Cornelius and Voltemand are Danish ambassadors sent by Claudius on an urgent diplomatic mission to Norway. Young Fortinbras, nephew of the king of Norway, has been belligerent, demanding the return of Norwegian lands originally conquered by the late King Hamlet. Technically, the King of Norway is in charge, but it seems that his whipper-snapper of a nephew is the one who's calling the shots.
Claudius wants Cornelius and Voltemand to go over Fortinbras's head and make a direct appeal to the king himself. Though aged and infirm, the king is still the dominant power in Norway, and—crucially—controls the country's armed forces. So Claudius hopes that the king can be persuaded to use his authority to put Fortinbras in his place and stop all this talk about demanding the return of what was originally Norwegian territory.