What is "postgasse"

The Postgasse is one of the streets in the Old City of Bern, the medieval city center of Bern, Switzerland. It is part of the Zähringerstadt which was built during the foundation of the city in 1191. It runs from Nydeggstalden near the Aare river in the east to the transverse Kreuzgasse, where the name changes to Rathausgasse. It is part of the UNESCO Cultural World Heritage Site that encompasses the Old City.