[@Nameless Hero] Well, he is nobility, if in exile. There's defiantly a president in history for nobles to be given command on the grounds of being noblemen and nothing else. Not to mention he's been formally educated in warfare for the batter part of his life. Even if he isn't experienced, I could see someone going 

"Oh, hey! This guy's been trained to understand the intricacies of war, but he isn't experienced enough to lead a larger unit. And he's a dragon rider so putting him in a supply unit would be a waste. I know! Let's make him a squad or team leader, so we can get him some experience and not risk too many lives doing it."