In 1688 he was named Vicar Apostolic for the nation (the Dutch Mission), although the Jesuits suspected and accused him of Jansenist sympathies.

On the second occasion he went to Rome in person, but his apologia did not satisfy his critics and he was finally suspended from his office in 1702 by Pope Clement XI (with his definitive discharge from the post coming in 1704, thanks to the intervention of Giovanni Battista Bussi).

Johannes van Neercassel, who governed the whole church in the Netherlands from 1663 to 1686, made no secret of his intimacy with the party.

Under Neercassel the country began to become the refuge of all whose obstinacy forced them to leave Kingdom of France and Spanish Netherlands as well as a number of priests, monks, and nuns who preferred exile to the acceptance of the pontifical Bulls.

He was summoned to Rome, defended himself so poorly that he was first forbidden to exercise his functions, and then deposed by a decree of 1704.