"I swear I will faithfully, loyally and honorably serve the Supreme Pontiff, and his legitimate successors, and also devote myself to them with all my strength, sacrificing my life to defend them if necessary. I take on these same duties with regard to the Sacred College of Cardinals whenever the See is vacant. Furthermore, I promise to the Captain Commander and to my other superiors respect, fidelity and obedience. This I swear! May God and our Holy Patrons assist me!"
Now that a new pope will soon be in the Vatican, I was curious about the Swiss Guard. I thought they were only for parades but they do protect the Pope and with modern weapons. They often work undercover in plain clothes.
Guards must be at least 5' 8", under 30 years old, unmarried, attended Swiss military school and be Catholics with a good reputation in their parishes.
"Swiss Guards travel everywhere with the Holy Father; the plainclothes bodyguards you see around the pope can consist of various agents, depending on what country the pope is visiting, but there are always two Swiss Guard officers among them."
More about the history:
A final thought: I wonder if the bright colorful uniforms help distract any potential attacker from the plain clothes guards hiding in the crowd, carrying the more lethal modern weapons?