Institutio Oratoria

But even in the case of an accusation of theft, just as in an accusation of murder, we enquire both into the act and the author, while in cases concerned with loans and deposits there are also two questions (though these are always distinct from one another), namely, whether the money was delivered and whether it has been repaid. Cases of adultery are marked by the following peculiarity, that, as a rule, the safety of two persons is involved, and it is necessary to say something of the past life of both, although some have raised the question whether both parties should be defended together. The line to be taken must depend on the circumstances of the individual case: if the defence of one party lends support to the defence of the other, I should defend them conjointly; if the reverse is the case, I should treat the two cases separately.

However, that no one may think me somewhat hasty in saying that two persons are as a rule involved in charges of adultery, I would point out that I would not assert that this is always the case. The woman alone may be accused of adultery with a person unknown: we may say,

Gifts were found in the house, and money from some unknown source, and love-letters whose destination cannot be ascertained.