https://en.wikipedia.org/wiki/Clandestine_church https://en.wikipedia.org/wiki/Clandestine_church Hidden chapels are fairly common in Europe during the Reforma

https://en.wikipedia.org/wiki/Clandestine_church https://en.wikipedia.org/wiki/Clandestine_church Hidden chapels are fairly common in Europe during the Reformation when one could not be a practicing Catholic in a Protestant country and vice versa.