Reason with

"Peace?"

As if he had heard the funniest joke of the century, Uther laughed very loudly. The man finally stopped his streak of laughter, before Emery thought the former had gone crazy. 

With an incredulous look on his face, he bellowed, "Are you serious?! You want to talk about peace when you threaten my life?"

Before Emery could respond to the man's outrage, Arthur said his piece first. "Please father, let's listen to him first!"

King Uther was about to continue his lashing when he heard that, causing the man to turn to his son with a glare. 

"Arthur! Did you hear what you just said yourself? If I didn't know you have been like this for a while, I would have believed this wizard had enchanted you! What exactly happened to you?!"

Arthur tried to convey his intention, "Father, all I want is the best for the kingdom… Actually I..." 

Alas, the king seemed utterly enraged as he interrupted his words.