It is narrated from Ibn Umar (may Allah be pleased with them both) that when Ghaylan bin Salamah Thaqafi (may Allah be pleased with him) accepted Islam, he had ten wives. The Prophet (ﷺ) said to him: "Keep four of them (in marriage) and separate from the rest."
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1191
Hadith Takhrijاسناده ضعيف : اخرجه الترمذي ، النكاح، باب ما جاء في الرجل يسلم وعنده عشرة نسوة (1128)۔ وقال سمعت محمد بن اسماعيل البخاري يقول: هذا حديث غير محفوظ ابن ماجه النكاح، باب الرجل يسلم وعنده اكثر من اربع نسوة (1953)۔
Nawfal bin Muawiyah (may Allah be pleased with him) narrated that I became Muslim while I had five wives. I asked the Prophet ﷺ, and he ﷺ said: "Divorce one and keep the remaining four (in marriage)." So I divorced the first of them, who had been barren for sixty years.
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1193
Hadith Takhrijاسناده ضعیف، لابهام شيخ الشافعي، وعوف بن الحارث فيه مقال، اخرجه البيقهى: 7 / 174 وفى المعرفة السنن والآثار له (4194)۔
It is narrated from Dailami or Ibn Dailami (may Allah be pleased with him), he said: "I embraced Islam and I had two real sisters in my marriage. I asked the Prophet (ﷺ), so he (ﷺ) instructed me to choose whichever one I wished from them and release the other."
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1194
Hadith Takhrijاخرجه الترمذى النكاح، باب ما جاء في الرجل يسلم وعنده أختان (1129) ، (1130) وقال ”حسن غریب“ وابن ماجة النكاح، باب الرجل يسلم وعنده أختان (1951) وابوداؤد ، الطلاق ، باب في من اسلم وعنده نساء اكثر من أربع أو اختان (2243)۔
It is narrated from Ibn Shihab (may Allah have mercy on him) that the Messenger of Allah (ﷺ) said to the man from the tribe of Thaqif who had accepted Islam and had ten wives: "Keep four and separate (divorce) the rest."
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1195
Hadith Takhrijاسناده ضعيف لإرساله: اخرجه البيقهى: 182/7 - وابو داؤد في المراسيل (234)- والدارقطني: 3/ 270- ومالك في الموطا الطلاق، باب جامع الطلاق۔
It is narrated from Ibn Shihab that Safwan bin Umayyah (may Allah be pleased with him) fled at the time of the conquest of Makkah, then came to the Messenger of Allah ﷺ and participated in the battles of Hunayn and Ta’if while still in a state of disbelief, whereas his wife had already embraced Islam. The Prophet ﷺ kept them both upon their (previous) marriage. Ibn Shihab said: There was approximately a one-month gap between the Islam of Safwan and his wife.
Hadith Referenceمسند الإمام الشافعي / كتاب النكاح / 1196
Hadith Takhrijاسناده ضعيف لإرساله اخرجه البيهقي في المعرفة السنن والآثار (4198) - ومالك في الموطأ، النكاح، باب نكاح المشرك اذا اسلمت زوجته قبله۔