What happens to the dower (Mahr) paid by non-Muslims who subsequently convert to Islam?
Chapter on Marriage of Polytheists
Al-Mughni
Book of Marriage
Primary text
When non-Muslims convert to Islam and submit their case after the marriage contract and the full receipt of the dower, their previous actions and receipts are not overturned. The dower they received is final, and they are not entitled to more, whether the specified dower was lawful or unlawful according to Islamic law. This is evidenced by the Quranic command to leave remaining usury (Quran 2:278) and the statement that whoever abstains after receiving admonition from his Lord has what preceded (Quran 2:275). Judicial intervention to invalidate previously transacted property is difficult due to the passage of time and extensive subsequent dealings, which could discourage conversion. Therefore, it is forgiven, just as the abandonment of prior obligatory religious duties is overlooked.
Supporting text
If the dower was not fully received, and the specified amount was lawful, it must be paid as stipulated in the contract. If the specified dower was unlawful, such as wine or swine, it is nullified and not enforceable by judgment. In such a case, if consummation occurred, the wife is entitled to the customary dower (Mahr al-Mithl); if separation occurred before consummation, she is due half of the customary dower. Abu Hanifa held that if specific prohibited items like wine or swine were named, she receives only those items. If they were unspecified, she receives the value for wine and the customary dower for swine, based on preference (Istihsan).