Perhaps the central figure in molding the Dutch reputation for tolerance is Hugo Grotius also known as a founder of International Law. He put forward that the only necessary laws were those for maintaining public order, and that religious doctrine should be left to the private beliefs of individuals.
In an attempt to resolve the theological disputes between followers of Arminius and Gomarus he was asked to draft an edict expressing an official state line of tolerance. However, this lead to local rebellion which nearly undermined the Republic. The danger provided Maurice of Nassau, who supported the hard-line Calvinist Gomarus, a chance to assert his authority. Grotius was arrested and imprisoned. Other proponents of openness and tolerance were executed.
Even today, I understand some towns in Eastern Holland retain their conservatism, while Amsterdam and Rotterdam have their own deserved reputations.
Popularly, at least when I was in elementary school, the Netherlands was known as the place which gave refuge to the Puritains who eventually founded the Massachusettes Bay colony, and gave England Cromwell. Dutch settlement in the Hudson river valley instilled the Patroon system, one of the most feudal arrangements of the colonial period. It continued well into the 19th century.
The Dutch Republic does hold the distinction of being the first European nation to recognise the American Colonies as a nation independent of Britain.
L'inteligence sans volonté n'aboutit ŕ rien, n'est-ce pas?... Mais, la volonté sans intelligence?... Catastrophe!... Celine