For over twenty years he was attached to the episcopal seminary of Liège, first as professor of dogmatic theology and later as its superior.
During this period the Jansenists were active in Belgium, both in attacking the Jesuits and in opposing the papal decrees condemnatory of Jansenism.
[1] In "Specimen doctrinæ a Jesuitis in Seminario Leodiensi traditæ" the Jesuits were accused, among other things, of corrupting faith and morals by their teaching.
In answer to another Jansenistic work known as the "Epistola Leodiensis de formula Alexandri VII", he published his "Vera defensio authoritatis Ecclesiæ" (Liège, 1707).
The Jansenist, Henry Denys, thereupon defended the "Epistola" in an anonymously published work which called forth Stephens's "Author epistolæ Leodiensis denuo confutatus" (Liège, 1709).