Our building on Prinsengracht 7, has a long and interesting history. During the 'Alteratie' in 1578, when the Catholics were not allowed to visit their churches, a lot of 'hidden churches' were built behind houses, so they could not be seen attending mass. In 1687 one of those churches was built in the basement or souterain of the building on the Prinsengracht 7, which was at that time a building which housed the postal coach, hence the name 'the Posthoorn'.
In 1760 the front of the house was changed and in 1836 the back of the house was built on the ruins of the old church. The apartement in the souterain (apartement 3) you can still see the marvel floor of the hidden church.
The story goes and is still told, that there was a tunnel which leads from the Prinsengracht 7 underneath the canal to the pub opposite, for the churchgoers to escape when they would be discovered during a mass. If you are in the Posthoorn you will frequently find a big group of people in front of the house when this story is told by the Amsterdam tour guides.