Ni hivi tangu year 1527 the Swiss Guards have had history with Vatican. During the 1527 sack of Rome when Spanish troops burnt the city and tried to kill Pope Clement VII,the Swiss Guards saved Pope clement.
Pope clement escaped through the secret tunnel that leads into the Vatican's Castel Sant'Angelo fortress, but 146 Swiss Guards protecting him from the rear as he fled massacre.
Although up until the 1980s the role of the Papal Swiss Guards was primarily ceremonial yet, after Pope John Paul IIs assassination attempt, this was severely revised to include modern combat training; and a higher priority was given to the guards ability to actually defend the Pope, his Home and the Vatican in general.
About the Swiss Guards credentials
it's very true.
The Swiss Guard must be a Swiss national, Catholic, unmarried, between the ages of 19 and 30, have undergone rigorous Swiss military training and be at least 174 cm tall. Once accepted, the terms of service can be as short as 2 years, and as long as 25. Now thats devotion!
Remember when the Turkish gunman Mehmet Ali Agca shot the pope in front of the crowd in St Peter's Square in 1981, a Swiss Guard in plain clothes jumped on the wounded pontiff to shield him from further attacks.