Final answer:
The skepticism towards King Claudius' letter to the King of Norway warning against Fortinbras' attack arises from literary and historical themes, where ambitions and political complexities often render such requests ineffective.
Step-by-step explanation:
King Claudius sends a letter to the King of Norway to persuade young Fortinbras to reconsider his plans to attack Denmark. The effectiveness of this letter is questionable because of several factors inherent in the dynamics of political power and warfare.
In literature and history, such requests often come too late or are ignored due to existing tensions and the ambitions of the parties involved. The urgency in Claudius' action echoes the ineffectiveness depicted in similar scenarios, where pleas and messages fail to deter the determined course of an aggressor.
Works like "Hamlet" and historical documents indicate that the might of ambition and the complexities of political alliances seldom bow to simple requests, especially when power and revenge are at stake.
This skepticism is heightened by the audience's knowledge of the usual futility of such letters in averting conflict, as exemplified in other literary and historical contexts.