For some years he was engaged in parochial duties, and combated the Anabaptist movement in Flanders with great zeal and success.
In 1625, he became secretary and almoner of Cardinal Alfonso de la Cueva, later becoming canon and scholaster of St Martin's Cathedral, Ypres.
Publication of the first volume of his sumptuously illustrated Flandria illustrata (1641) nearly bankrupted him, and he was rescued from ruination by an award of 1,000 florins through the Lille Chamber of Accounts.
He soon found himself compelled to claim the hospitality of the Benedictine Abbey of Afflighem, since he had reduced himself to absolute poverty by the publication of numerous works.
He combined high intellectual gifts with great zeal, and left behind forty-two printed, and almost as many unprinted, works.