First church visited in Leiden: Marekerk. Architecture may be reminiscent of a Catholic church, but our guide told us that it is a Protestant church. The building is majestic, a round dome overlooking it, and it is still used by the Protestant community of Leiden. The past and current relations between Catholics and Protestants in Leiden are relatively complicated, and certainly competitive, as everywhere else. We did not expect it. Nor did we expect so many churches and stories in this city.