This Jesuit church near the Flower Market began its existence in the 17th century as a clandestine house of worship hidden behind the façade of a typical canal house. Catholics were persecuted at the time and had to gather in secret so it was given the code name of ‘de Krijtberg’ or Chalk Mountain, because the owner of the house was a merchant who had dealings with England known throughout Holland by its white chalk cliffs of Dover. The current neo-Gothic structure was erected between 1880 and 1883 replacing the previous medieval building, which explains why it is so incredibly narrow. It is perhaps best known for its impressive collection of stained glass. The more vibrant panes were added in 1930, while the more faded examples are original.