Swiss soldiers began guarding Vatican City in 1506.
At the time Swiss Cantons were very poor, and men started emigrating to other places in hopes of finding a better future. Most of the jobs available to immigrants were as soldiers. Swiss soldiers were seen as loyal, courageous, and hard-working, and as a result Pope Julius II invited them to protect him and the Vatican.
This article briefly talks about what makes the City of Florence such a magical place where people wander about can experience awestruck, and how is this a widely accepted truth.