A man who marries a woman, consummates the marriage, and she turns out to be within his prohibited degrees

Ibrahim (may Allah have mercy on him) said: If a man marries a woman who is a mahram to him and has intercourse with her, the woman is entitled to the dower.

Al-Hasan (may Allah have mercy on him) said: Whatever dower the woman has taken is hers.

Something similar is reported from Hammad (may Allah have mercy on him).

Al-Sha'bi (may Allah have mercy on him) said: The woman will not receive a dower, whether the man consummated the marriage or not. Would a man give a dower to his sister or his mother?

Ibrahim (may Allah have mercy on him) said: If a man unknowingly marries his foster sister and then learns of it afterwards, the marriage is void. If he has consummated it, the dower is due because he made her private part lawful for himself; and if he has not consummated it, the two will be separated without a dower.

Al-Hakam (may Allah have mercy on him) said: If a man unknowingly marries his foster sister or his wife's foster sister and then consummates the marriage, she is entitled to the full dower.

Al-Hasan (may Allah have mercy on him) said: She is entitled to the dower because of what he did.

Hammad (may Allah have mercy on him) said: In every act of intercourse in which the hadd punishment is not applied, the full dower is due.

Tawus (may Allah have mercy on him) said: If a man unknowingly marries his foster sister and also has intercourse with her, the two will be separated, and the woman will not receive the full dower, but rather a part of it.