More than 500 years after the first Swiss men stepped inside the Vatican walls as "Defenders of the Church's freedom", David Geisser donned his robes as a Swiss Guard.

“My father was a Swiss Guard and when I was little he told me a lot about it," the 24-year-old tells The Local.

"We came to Rome often and I really like Italian culture.” 

But despite being the son of a guard, Geisser still had to go through military school in Switzerland before being able to apply to work at the Vatican.

He also needed to fulfill other strict requirements which, aside from education, cover everything from height to marital status and morals.

Geisser passed all the tests and joined the Vatican ranks in February 2013, just weeks before Pope Benedict XVI made his shock resignation and Pope Francis was elected as the pontiff’s successor.

Aside from his military background, the young guard is also a trained chef and made headlines last week when he published a cookbook filled with recipes favoured by popes.

“The head of the Swiss Guard asked me if I could write another book; I said yes because I love to cook,” says Geisser, who spent three years studying to be a chef and has already authored two other recipe books.

Geisser wrote “Bon Appetit, Swiss Guard” in his free time and requested Pope Francis’ menu from the pontiff’s secretary, including the sweet Argentine dessert "Dulche de Leche".

Although originally published in German, the cookbook will soon be available in other languages including English and Italian.

But as one of just 110 guards — the world’s smallest military — Geisser had no time to neglect his duty as the Pope’s protector.

“The Swiss Guards are always close to him, we’re responsible for his security day and night,” he says.

“We’re with him during the general audiences and also protect the historic buildings.”

While working life is a far cry from the front-line battles fought by Geisser’s ancestors, the Swiss Guard says the job is enjoyable but can be tough.

“It’s not easy to stand in one place for two hours,” he says of a duty presumably made all the harder by the throngs of tourists taking photographs of the Swiss Guards.

Aside from maintaining Vatican security, the guards have to carry out inspections and take part in marches and shooting practice.

They also have a musical side, with the Swiss Guard band and a choir, in addition to playing sports such as football and table tennis.