Canon X.

If any who have lapsed have been ordained through the ignorance, or even with the previous knowledge of the ordainers, this shall not prejudice the canon of the Church; for when they are discovered they shall be deposed.

Notes.

Ancient Epitome of Canon X.

Whoso had lapsed are to be deposed whether those who ordained and promoted them did so conscious of their guilt or unknowing of it.

Hefele.

The tenth canon differs from the ninth, inasmuch as it concerns only the  lapsi and their elevation, not only to the priesthood, but to any other ecclesiastical preferment as well, and requires their deposition. The punishment of a bishop who should consciously perform such an ordination is not mentioned; but it is incontestable that the  lapsi could not be ordained, even after having performed penance; for, as the preceding canon states, the Church requires those who were faultless. It is to be observed that the word προχειρίζειν is evidently employed here in the sense of “ordain,” and is used without any distinction from χειρίζειν, whilst in the synodal letter of the Council of Nicæa on the subject of the Meletians, there is a distinction between these two words, and προχειρίζειν is used to signify  eligere .

This canon is found in  Corpus Juris Canonici .  Decretum . Pars I. Dist. lxxxi. c.v.