Yevamot 76B

הא לא צריכא ליה.

But this one, Pharaoh’s daughter, did not require such things, as she herself was the daughter of royalty, and therefore there would have been no reason to doubt the sincerity of her conversion.

[ותיפוק ליה] דהא מצרית ראשונה היא! וכי תימא: הנך אזלי לעלמא והני אחריני נינהו,

The Talmud asks: But let him derive that Pharaoh’s daughter was forbidden to Solomon for a different reason, as she was a first-generation Egyptian convert. Even if she converted, she would still have been an Egyptian convert of the first generation, and as such neither she nor her children would have been permitted to marry a Jew by birth (Deuteronomy 23:8–9). And if you would say that those whom the Torah rendered forbidden have already left Egypt and are now living elsewhere in the world, and those currently living in Egypt are others, there is a difficulty.

והא תניא, אמר רבי יהודה: מנימין גר מצרי היה לי חבר מתלמידי רבי עקיבא, אמר: אני מצרי ראשון, ונשאתי מצרית ראשונה. אשיא לבני מצרית שניה כדי שיהא בן בני ראוי לבא בקהל!

As, isn’t it taught in a baraita that R' Yehuda said: Minyamin, an Egyptian convert, was a friend of mine from among the students of R' Akiva, and he said: After I converted I was a first-generation Egyptian convert, and so I married another first-generation Egyptian convert. I will marry off my son, who is a second-generation Egyptian convert, to another second-generation Egyptian convert, so that my grandson will be fit to enter into the congregation. This indicates that first- and second-generation converts of Egyptian extraction were prohibited from entering into the congregation even during the period of the Mishnah.

אמר רב פפא: אנן משלמה ליקו ונתיב? שלמה לא נסיב מידי, דכתיב ביה: ״מן הגוים אשר אמר ה׳ אל בני ישראל לא תבואו בהם והם לא יבואו בכם אכן יטו את לבבכם אחרי אלהיהם, בהם דבק שלמה לאהבה״. אלא קשיא ״ויתחתן״!

Rav Pappa said: should we stand up and raise an objection from Solomon? Solomon did not marry anyone, as it is written in his regard: “Of the nations concerning which YHWH said to the children of Israel, You should not go among them, neither should they come among you; for surely they will turn away your heart after their gods; Solomon cleaved to these in love” (I Kings 11:2). Solomon cleaved to these women in love, but was not legally married to them. As Solomon had other forbidden wives, the case of Pharaoh’s daughter presents no special difficulty. In fact, none of these marriages were valid at all. But the phrase “and Solomon married” (I Kings 3:1) that appears in connection with Pharaoh’s daughter is difficult, as it indicates that this marriage was in fact valid.