Is a marriage contract concluded in a mosque valid after the wife's conversion to Islam from atheism, and if she is divorced, does that divorce take effect?

As long as the offer and acceptance were issued by you and the wife in writing and duly documented, then this marriage is not without those who affirm its validity, for the following reasons: 1. The validity of marriage without a guardian (wali) according to Abu Hanifa, Zufar, Al-Sha'bi, and Al-Zuhri. 2. The occurrence of offer and acceptance through writing, according to some scholars.

Accordingly, divorce occurs in this disputed contract and counts towards the three divorces; and the well-known opinion of Malik and Ahmad is that divorce occurs in a disputed, invalid marriage.