The story
The earliest recorded mention of St. Peter Stiftskulinarium was in a letter to Charlemagne written in 803 AD. Local legend states that Christopher Columbus, Johann Georg Faust, and Wolfgang Amadeus Mozart ate at the restaurant. In its early history, the restaurant gave food for free to religious pilgrims. French soldiers were given quarters in the inn during the Napoleonic Wars. In modern times it has served political figures such as Bill Clinton, Alexander Van der Bellen, and other European leaders.
As the restaurant has closed a few times throughout its history, it is not the oldest continuously-operating restaurant in the world; that was Sobrino de Botín in Spain, which had operated since 1725 prior to closing temporarily during COVID.
From Wikipedia’s article on St. Peter Stiftskulinarium, shared under CC BY-SA 4.0.4