Sejanus, whom they already suspected of overweening ambition.
Ann Book III Chapter 29: Appointments and marriages

He had a body which could endure hardships, and a daring spirit. He was one who screened himself, while he was attacking others; he was as cringing as he was imperious; before the world he affected humility; in his heart he lusted after supremacy, for the sake of which he sometimes lavish and luxurious, but oftener energetic and watchful, qualities quite as
Ann Book IV Chapter 1: Seianus ambition. His background