Task: Question Answering
Input (English): The Dutch Reformed Church remained the largest church body in the Netherlands until the middle of the 20th century, when it was overtaken by the Roman Catholic Church. The rapid secularisation of the Netherlands in the 1960s dramatically reduced participation in the mainstream Protestant church. From the '60s onward, a number of attempts were made to effect a reunion with the Reformed Churches in the Netherlands . This led to the two churches uniting with the Evangelical Lutheran Church in the Kingdom of the Netherlands  to establish the Protestant Church in the Netherlands in 2004. The 2004 merger led to a separation in which a number of congregations and members of the Dutch Reformed Church separated to form the Restored Reformed Church . Estimations of their membership vary from 35,000 up to 70,000 in about 120 local congregations served by 88 ministers. The Restored Reformed Church disapproves of the pluralistic nature of the merged church, which they allege contains partly contradicting Reformed and Lutheran confessions. This conservative group also opposes the ordination of women and the blessing of same-sex unions in Christian churches, which have been adopted as practices by the merged church. 
Question: WHAT HELPED THE ROMAN CATHOLIC CHURCH TO BECOME THE LARGEST CHURCH BODY IN THE NETHERLANDS ?
Output (English): rapid secularisation