Toward the end of 1598 he went to Leuven where doubts arose in his mind which ultimately led him to break with Catholicism.
After a few weeks at Gouda, where his foster relations rejected him, he sought refuge in the house of his parents, where he studied Reformed tenets, meanwhile seeking occupation to gain his livelihood.
In 1617 he received leave of absence to the Reformed church at The Hague (the Counter-Remonstrants meeting in the Kloosterkerk), and was a deputy of the provincial synod of North Holland to the Synod of Dort, which appointed him a member of the committee to draw up the Canons of Dort.
[3] His own distinctive view traced the Protestant Reformation back to Wessel Gansfort, and claimed that the doctrine of election in Philipp Melanchthon and Heinrich Bullinger was compatible with the outcome of the Synod of Dort.
He opposed civil intervention in ecclesiastical affairs in his Antwoordt op drij vraghen dienende tot advys in de huydendagsche kerklijke swarigheden (1615), and his Christelijcke ende nootwendighe verclaringhe (1615).