The architect A. C. Bleys designed this church with its dark and eerie interior as a replacement for all the clandestine Catholic churches that operated during the Reformation. After the Oude Kerk and the Ons' Lieve Heer op Solder (Our Lord in the Attic) chapel, this church, built in 1887, became the third and (probably final) Sint Nicolaas church in Amsterdam. Saint Nicholas, the all-purpose patron saint of children, thieves, prostitutes, sailors, and the City of Amsterdam, transforms into Sinterklaas in mid-November when he is popularly said to arrive from Spain on a steamboat with his helper Zwarte Piet (Black Pete). The eve of his birthday on December 6 is celebrated as a family feast when everyone exchanges presents and poems. In recent years, the Black Pete phenomenon has received a lot of flak, with some claiming that Sinterklaas's sidekick is nothing but a slave. There are daily tours in the church for groups with a minimum of seven participants. Call for reservations on Thursday 10–noon. The church hosts a Gregorian chant vesper service on Sunday at 5 September–June (free).