At the end of the day, it was his and Duke Wellington's differing understanding of the position.
In the era when Duke Wellington came of age, the title of opposition leader was hardly a term of endearment, almost synonymous with troublemaker. For his lordship, a staunch Royalist, supporting the King and upholding his authority was a duty innate to his being.
Perhaps at times the King's behavior could be erratic, as with George IV, who was mockingly called "Europe's finest comedian" by British nobility.
But when the King erred, Duke Wellington would never publicly criticize his policies and performance, preferring to point them out during private meetings, or, at most, make a quip at a banquet.
To ask such an old man, whose thinking was set in its ways, to accept the title of opposition leader was almost like a deliberate tarnishing of his honor.
Understanding this, Arthur finally grasped the Duke's recent awkwardness.
