The word itself in its etymological sense, signifies the desertion of a post, the giving up of a state of life; he who voluntarily embraces a definite state of life cannot leave it, therefore, without becoming an apostate. Most authors, however, distinguish with Benedict XIV (De Synodo diecesana, XIII, xi, 9), between three kinds of apostasy: apostasy a Fide or perfidie, when a Christian gives up his faith; apostasy ab ordine, when a cleric abandons the ecclesiastical state; apostasy a religione, or monachatus, when a religious leaves the religious life. The Gloss on title 9 of the fifth book of the Decretals of Gregory IX mentions two other kinds of apostasy: apostasy inobedientiae, disobedience to a command given by lawful authority, and iteratio baptismatis, the repetition of baptism, "quoniam reiterantes baptismum videntur apostatare dum recedunt a priori baptismate". As all sin involves disobedience, the apostasy inobedientiae does not constitute a specific offense. In the case of iteratio baptismatis, the offence falls rather under the head of heresy and irregularity than of apostasy; if the latter name has sometimes been given to it, it is due to the fact that the Decretals of Gregory IX combine into one title, under the rubric "De apostatis et reiterantibus baptisma" (V, title 9) the two distinct titles of the Justinian Code: "Ne sanctum baptisma iteretur" and" De apostatis " (I, titles 6, 7), in Corpus juris civilis ed. Krueger, (Berlin, 1888); II 60-61. See Munchen "Das kanonische Gerichtsverfahren und Strafrecht" (Cologne, 1874), II, 362, 363. Apostasy, in its strictest sense, means apostasy a Fide (St. Thomas, Summa theologica, II-II, Q. xii a. 1).