Gregory to Romanus the guardian, Fantinus the guardian, Sabinus the sub-deacon, Sergius the guardian, Boniface the guardian (a paribus  ), and the six patroni.
Since, even as cautious foresight knows how to block the way against faults, and to avoid what is hurtful, so neglect opens the way to excesses, and is wont to incur what ought to be guarded against, we ought to bestow very careful attention, and see alike to the reputation and to the safeguard of our brethren and priests. Now it has come to our ears that certain of the bishops, under pretext, as it were, of help, associate themselves in one house with women. And so, lest hereby just occasion of detraction should be given to scoffers, or the ancient enemy of the human race should take advantage of an easy matter of deceit, we enjoin thee by the tenor of this mandate that thou study to shew thyself strenuous and solicitous. And, if any of the bishops included within the limits of the patrimony committed to thee are living with women, do thou entirely put a stop to this, and for the future by no means suffer any women to reside with them, except such as the censorship of the sacred canons allows, that is a mother, an aunt, a sister, and others of this sort, concerning whom there can be no ill suspicion. Yet they do better, if they refrain from living together even with such as these. For we read that the blessed Augustine refused to live even with his sister, saying, Those who are with my sister are not my sisters.
The caution, then, of a learned man ought to be a great instruction to us. For it is a mark of uncautious presumption for one that is less firm not to fear what a strong man is afraid of. For he wisely overcomes what is unlawful who has learnt not to use even what is allowed him: and indeed we bind none in this matter against their will, but, as physicians are accustomed to do, we prescribe carefulness for health's sake, even though it be for the time distressful. And therefore we impose no necessary obligation; but, if any should choose to imitate a learned and holy man, we leave it to their own will. Let, then, thy Experience act with zeal and solicitude for the observance of what we have ordered to be prohibited. For, if hereafter it should chance to be found otherwise, know that thou wilt incur no slight risk with us. Furthermore, let it be thy care to exhort these same bishops, our brethren, that they admonish those who are subject to them, to wit those who are constituted in sacred orders, to observe in all ways after their example what they themselves observe; this only being added, that these, as canonical authority has decreed, are not to leave wives whom they ought to govern chastely. Given in the month of March, Indiction 2.
 See I. 25, note 8.