The pillars at the Strait were supposed to have carved on them Non plus ultra (‘Nothing beyond this’). So Charles took as his motto Plus ultra (in effect ‘Go further’) to boast that his subjects had passed the Straits and conquered the New World. In other words he had exceeded Hercules and laid claim to be the law-giver not just of Europe but of perhaps the whole planet. These formed part of the heraldic battery that so spooked his opponents and added to the sense of limitless Habsburg power.
