Halberds in hand, their armour polished and multicoloured pantaloons perfectly pressed, 36 new recruits to the Swiss Guards were sworn in on Friday with a vow to protect the pope.
Pope Francis had earlier received the latest members of the world's smallest army -- they total 135 -- before the guards pledged their "respect, loyalty and obedience" to the pontiff in a ceremony in the Paul VI hall at the Vatican.
The pope, 85, said they were consecrating several years "to a task that is both fascinating and full of responsibility in the heart of the universal church".
He noted those who had "shed their own blood" in the task of protecting the pontiff, on a day marking the death of 147 Swiss Guards while defending pope Clement VII during the "Sack of Rome" in 1527.
When they sign up, the guards must be practising Roman Catholics, Swiss citizens, aged between 19 and 30, measure at least 1.47 metres tall and be single -- although they can marry later.
They commit to safeguarding the pope for at least 26 months.
They and their families live in the Vatican in barracks designated a UNESCO world heritage site.
Plans are afoot to renovate the barracks, for which funds are being raised by a patronage committee in Switzerland, although work is not expected to begin until at least 2025.
When they leave service, the guards must return their distinctive red, yellow and blue striped outfits unless they have served for more than five years.
"After death, the uniforms must be returned, or be placed with the deceased in his coffin," Swiss Guards tailor Ety Cicioni told AFP.