Swiss Guards are the Swiss soldiers who have served as bodyguards, ceremonial guards, and palace guards at foreign European courts since the late 15th century. Apart from household and guard units, regular Swiss mercenary regiments have served as line troops in various armies; notably those of France, Spain and Naples up to the 19th century (see Swiss Mercenaries). In contemporary usage, the name Swiss Guards generally refers to the Pontifical Swiss Guard of Holy See.
Various units of Swiss Guards existed for hundreds of years. The earliest such unit was the Swiss Hundred Guard (Cent Suisses) at the French court (1497 – 1830). This small force was complemented in 1567 by a Swiss Guards regiment. The Papal Swiss Guard (now located in the Vatican City State), was founded in 1506 and is the only Swiss Guard that still exists. In the 18th and early 19th centuries several other Swiss Guards existed for periods in various European courts.
The use of Swiss soldiers as Royal guards and as the Pontifical guard stems from the reputation of Swiss mercenaries at the time of their formation. Since Switzerland was a poor country, young men often sought their fortunes abroad. Having a reputation for discipline and loyalty, and employing revolutionary battle tactics, they were considered the most powerful troops of the 15th century, until their methods were refined by the Landsknechte in the early 16th century.