In the first place, the name Devil is commonly given to the fallen angels, who are also called Demons. The exact technical distinction between the two terms in ecclesiastical usage may be seen in the phrase used in the decree of the Fourth Lateran Council[1]: “Diabolus enim et alii dæmones.” (The devil and the other demons), i.e. all are demons, and the chief of the demons is called the Devil. This distinction is preserved in the Vulgate New Testament, where _diabolus_ represents the Greek διάβολος, and in almost every instance refers to Satan himself, whilst his subordinate angels are described, in accordance with the Greek, as _dæmones_ or _dæmonia_. But save in some highly specialized context when the most meticulous accuracy is required, we now use the words “devil,” “demon” indifferently, and employ the definite article to denote Lucifer (Satan), chief of the devils, The Devil. So in S. Matthew xxv. 41, is written “the devil and his angels.” The Greek word διάβολος means a slanderer, an accuser, and in this sense is it applied to him of whom it is said “the accuser [ὁ κατήγορος] of our brethren is cast forth, who accused them before our God day and night” (Apocalypse xii. 10). Thus it answers to the Hebrew name Satan, which signifies an adversary, an accuser. Mention is made of the Devil in many passages both of the Old and New Testaments, but much is left in obscurity, and the full Scriptural teaching on the legions of evil can best be ascertained by combining the scattered notices and reading them in the light of patristic and theological tradition. The authoritative teaching of the Church is declared in the Decrees of the Fourth Lateran Church (cap. 1. _Firmiter credimus_), wherein, after setting forth that God in the beginning had created two creatures, the spiritual and corporeal; that is to say, the angelic and the earthly, and lastly man, who was made of both earth and body; the Council continues: “For the Devil and the other demons were created by God naturally good; but they themselves of themselves became evil.”[2] The dogma is here clearly laid down that the Devil and the other demons are spiritual or angelic creatures created by God in a state of innocence, and that they became evil by their own free act. It is added that man sinned by suggestion of the Devil, and that in the next world the reprobate and impenitent will suffer punishment with him. This then is the actual dogma, the dry bones of the doctrine, so to speak. But later theologians have added a great deal to this,—the authoritative Doctor Eximius, Francisco Suarez, S.J.,[3] _De Angelis_, VII, is especially valuable—and much of what they deduce cannot be disputed without such rejection incurring the grave censure technically known as “Erroneous.”[4]