On 26 May 1578, the day on which the so-called Alteration took place, Amsterdam changed from a Catholic city into a Protestant one. In a bloodless revolution, the Protestants took over the reins of government. The Catholic town council was expelled and Catholics were forbidden to worship in public.
After the Alteration, Amsterdamís monasteries and convents were dissolved by the civic authorities. The new Municipal Orphanage (Burgerweeshuis), intended for the orphaned children of citizens of Amsterdam, was established in the former Convent of St Lucy, which had been founded in 1414. This complex now houses the Amsterdam Historical Museum.