Oude Kerk is next to being a museum, a church, and a young contemporary art institution also a national monument. The museum is the oldest building of Amsterdam and has been the main church of the city for a long time, playing an important social role throughout the ages. The Oude Kerk was Roman Catholic at first, as it also functioned as a cemetery and archive. However, after the Alteration of 1578, it was converted into a Protestant church. Over the last century, the Oude Kerk became one of the landmarks of the city and central to the redlight district of Amsterdam.