This article presents two events that are almost 500 years apart and historically have nothing else in common but that they both used the Basel Cathedral as a meeting place: the Council of Basel in the early 15th century and the Peace Congress of the Second International in 1912. For both events, the paper examines the role played by the use of the Cathedral, the function ascribed to the Cathedral and, conversely, the influence the Cathedral as a church building had on the two events. While, for the Council, the Cathedral only played a role beyond its usual functionality during the election of the Pope (as a replacement for St. Peter's), it can be shown that its use by the Second International was to become a special feature of this Peace Congress and caused a correspondingly large echo.