From the Letter of the Same, to Probus

We establish, the Catholic faith supporting it, that that is the marriage which was first founded by divine grace, and that the coming together of the second woman (whom someone had married because his wife was being held captive), the former wife surviving and not cast out by divorce, can in no way be legitimate.

Cf. Decree VI from the letter to Exuperius and Thesis XVIII, VI, at the end.