This vital work was originally published in 1681 in Venice and republished in 1861 in Constantinople. It was regarded so highly that in the preface the following is said: "It is entitled generally A Catechism because of the character and manner of the instruction, which with a view to its being clearer and more easily engraven on the memory, gently pours out the divine thoughts in question and answer, as from the stream at a fountain head, sweet and clear, copying both the clearness and the flow. But the largest and chief part of it is occupied with what concerns the divine Initiation, all which the learned and interesting Nicolas collected and culled from all the more ancient commentators..."