Significance of King Claudius speech in act 1, scene 2. What does it mean, what exactly is he on about!?

Claudius has secured the throne by first killing his brother, Hamlet, and marrying his sister-in-law Gertrude which is not allowed in many religions as being uous. He is addressing the court because the king of Norway has a nephew named Fortinbras who wants the new King Claudius to return certain lands formerly given to Hamlet the Elder and now devoid of a pact any longer since the elder has died and Fortinbras is to be the new ruler and not bound by promises and treaties made by others. Claudius refuses to give in and makes the choice public with this court appearance as well as sending Cornelius and Voltimand with a letter to the old king to let him know what the nephew is doing while he is sick and old. The two courtiers have no power to negotiate, only to inform and their presence at the court of Norway will indeed require something to be done or discussed.