As we noted two days ago, eight of the twelve books of St John Cassian’s Institutes for Monasteries treat of the principal vices which monks must struggle to overcome, and yesterday, we saw the Greek word which he uses in book five for the vice of gluttony, “gastrimargia.” The eleventh book deals with a vice to which he also gives a Greek name, “cenodoxia”, a compound of “kenos – empty” and “doxa – glory.” Under his influence, the word was known throughout the Middle Ages, and even appears in one of the prayers in the Roman Missal. The English translation of it, “vainglory”, is obviously based on it, but the Latin equivalent, “vanigloria”, is late and rare.
Here is the conclusion of Cassian’s words on the subject, in which he identifies the remedies for it.
“… athleta Christi, qui verum ac spiritalem agonem legitime certare desiderat, hanc multiformem variamque bestiam omnimodis superare festinet, quam nobis ex omni parte velut multiplicem nequitiam occurrentem tali remedio poterimus evadere, ut cogitantes illud Davidicum eloquium: Dominus dissipavit ossa eorum, qui hominibus placent. Primitus nihil proposito vanitatis et inanis gloriae capessendae gratia nosmetipsos facere permittamus. Deinde ea quae bono initio fecerimus, observatione simili custodire nitamur, ne omnes laborum nostrorum fructus post irrepens cenodoxiae morbus evacuet. Quidquid etiam in conversatione fratrum minime communis usus recipit, vel exercet, omni studio ut jactantiae deditum declinemus, et ea quae nos possunt inter caeteros notabiles reddere, ac veluti solis facientibus laus apud homines sit conquirenda, vitemus. His enim vel maxime indiciis cenodoxiae lethale contagium nobis inhaerere monstrabitur; quod facillime poterimus effugere, si consideremus non solum fructum laborum nostrorum nos penitus amissuros, quoscumque cenodoxiae proposito fecerimus, sed etiam reos magni criminis factos, aeterna supplicia velut sacrilegos soluturos; utpote qui ad injuriam Dei opus, quod ejus obtentu nos oportuit agere, hominum gratia maluimus exercere, ab eo qui occultorum est conscius, homines Deo, et gloriam mundi gloriae Domini praetulisse convicti.
(The Allegory of Vanity, 1632-36, by the Spanish painter Antonio de Pereda (1611-78))

… the athlete of Christ who desires to strive lawfully in this true and spiritual combat, should hasten by all means to overcome this many-formed and variable beast, which, as it meets us on every side like some manifold wickedness, we shall be able to avoid by such a remedy as this; thinking on that saying of David, ‘The Lord has scattered the bones of those who please men.’ (Ps. 52, 6) From the first, let us not allow ourselves to do anything with the suggestion of vanity, and for the sake of obtaining vainglory. Then, let us strive with the same care to maintain what we have begun well, lest afterwards the malady of vainglory should creep in and make void all the fruits of our labours. And anything which is of very little use or value in the common life of the brethren, let us avoid as something which leads to boasting, along with all things that can render us noteworthy among the others, and likewise, those things for which credit would be gained among men, as if we were the only people who did it. For by these signs especially, the deadly taint of vainglory will be shown to cling to us: but we shall be able to avoid it most easily, if we consider that we shall not only completely lose the fruit of those labors of ours which we have performed at the suggestion of vainglory, but that we shall also be made guilty of a great sin, and as impious persons undergo eternal punishments, inasmuch as we have wronged God by doing for the favor of men what we ought to have done for His sake, and are convicted by Him who knows all secrets of having preferred men to God, and the praise of the world to the praise of the Lord.”