Born at Pittem near Bruges, he went at an early age to Leuven. He was teaching theology and literature in 1541 at Bruges and shortly afterwards at Ghent. About 1549 he moved to Cologne, where, after a profound study of the points of difference between the Catholic and reformed churches, he devoted himself to the project of reunion, thus anticipating the efforts of Gottfried Leibniz. He died at Cologne on 3 February 1566. The collected edition of his works was published in 1616 at Paris.
In 1561 he published anonymously De officio pii ac publicae tranquillitatis vere amantis viri in hoc religionis dissidio (Basel), in which, while holding that no one, on account of abuses, has a right utterly to subvert the Church, he does not disguise his dislike of those who exaggerated the papal claims. He takes his standpoint on Scripture explained by tradition and the fathers of the first six centuries.
At a time when controversy drowned the voice of reason, such a book pleased neither party; but as some of the German princes thought that he could heal the breach, the emperor Ferdinand asked him to publish his Consultatio de Articulis Fidei lute, Catholicos et Protestantes Controversis (1565), in which, like Newman at a later date, he tried to put a Catholic interpretation upon Protestant formularies.
While never attacking dogma, and even favouring the Roman church on the ground of authority, he criticizes the papal power and makes reflections on practices. The work, attacked violently by the Leuven theologians on one side, and by Calvin and Beza on the other, was put on the Roman Index in 1617.