What are some reasons why the throne has to be filled so quickly, after the murder of Duncan?newspaper article :)
The most pressing issue was the approach of Fortinbras, a political and military foe. Also, the succession of a dynasty depended on immediate and unequivocal agreement on a successor, and since Hamlet was next in line, it was imperative for Duncan to marry Gertrude in order to secure the succession for himself, through the legitimate queen. Of course, the real reason lies in the dramatic development – Shakespeare was introducing the first complication. This haste was unseemly in Elizabethan England also, and the queen was very concerned with questions of her own succession, since she had no offspring. Shakespeare steers clear of any direct political parallel (which he also avoided in his histories), but the Elizabethan audience would recognize the inherent drama in a situation where succession was in question.