VATICAN CITY — Maximilian Fischer, 20, is one of the new recruits to an institution that has been protecting popes since the 16th century: the Swiss Guard.

Known to tourists in St Peter's Square for its colorful yellow, red and blue uniforms and ceremonial halberd weapons, the "world's smallest army" comprises Swiss Catholics aged between 19 and 30 and it remains all male.

"My mom always made these jokes that when I was older, I could go to the Swiss Guards because I was Swiss," Fischer told Reuters.

Fischer did military service in Switzerland where he learned that he ticked other boxes to join the Guard, whose members must be deemed of "impeccable character" as well as being at least 1.74 meters (5 feet 7 inches) tall.

"When I was done with the military, I looked it up and I was like 'Yeah why not? Let's try to get in,' and now I'm here. I'm enjoying it very much, and it's amazing," added Fischer, who is from the small town of Ruswil.

During the swearing-in ceremony, the new recruits to the 135-strong force knelt before Pope Francis, raised three fingers on their right hand to represent the Holy Trinity and swore an oath to serve the pontiff to the death.

"It's not 100% just being the police of the Vatican, but I very much value Pope Francis," said Fischer. "I very much agree with his values, and I think for me it's an honor to protect him," he added.

The Swiss Guard was founded by Pope Julius II in 1506.

It has expanded from 110 members under Pope Francis in time for the 2025 Holy Year when millions of additional pilgrims are expected to visit the Vatican.

The swearing-in ceremony is held on May 6, commemorating the date in 1527 when 147 Guards were killed defending Pope Clement VII from an attack by the forces of the Holy Roman Emperor Charles V.

Swiss Guards sign up for a minimum of 26 months. They must be single when they join but can marry once they are aged over 25 and have served for more than five years. — Reuters