Calvinism became the theological system of the majority in the Netherlands during the Dutch Revolt in the Eighty Years War. Other religions were tolerated, but could not practice their religion in public. The Netherlands today is one of the most secular countries in Europe. An estimated 49.6% of the population (2007) call themselves non-religious. The remaining are 15.7% Protestant, 27% Roman Catholic, and 5.3% Muslim.
In former ages, Protestantism used to be the largest religion in the Netherlands , but there has always been a high percentage of Roman Catholics, who were strongly predominating in the southern provinces, but also considerably present in the northern ones. However, over the past century the older Protestant churches have been in decline. Islam has begun to gain a foothold and mosques are being built. The Netherlands is also home to a significant Hindu minority, mostly made up of migrants who came from former colony Suriname after its independence.