|photo property of the guardia svizzera official website|
These soldiers have served to protect the pope since 1506 in his home (they don't travel with him.) Though they still wear the same uniform that they did then, the guards are actually super well trained security professionals, completely skilled in modern defense and all Catholic.
The pontif's guard were originally mercenaries. They were the top pick at the time, because they'd be loyal to anyone who was paying. As we read in previous posts, before the Helvetic Confederation formed, there was just a clump of non-citizens and they were apparently an army for hire. So the Pope (Pope Julius II) done hired 'em.