Yevamos15: 1
הָאִשָּׁה שֶׁהָלְכָה הִיא וּבַעְלָהּ לִמְדִינַת הַיָּם, שָׁלוֹם בֵּינוֹ לְבֵינָהּ וְשָׁלוֹם בָּעוֹלָם, וּבָאתָה וְאָמְרָה — ,,מֵת בַּעְלִי” — תִּנָּשֵׂא. ,,מֵת בַּעְלִי” — תִּתְיַבֵּם. שָׁלוֹם בֵּינוֹ לְבֵינָהּ וּמִלְחָמָה בָעוֹלָם, קְטָטָה בֵּינוֹ לְבֵינָהּ וְשָׁלוֹם בָּעוֹלָם, וּבָאתָה וְאָמְרָה ,,מֵת בַּעְלִי” — אֵינָהּ נֶאֱמֶנֶת. רַבִּי יְהוּדָה אוֹמֵר: לְעוֹלָם אֵינָהּ נֶאֱמֶנֶת, אֶלָּא אִם כֵּן בָּאתָה בוֹכָה וּבְגָדֶיהָ קְרוּעִין. אָמְרוּ לוֹ: אַחַת זוֹ וְאַחַת זוֹ תִּנָּשֵׂא.
A woman who went with her husband overseas, [and] there was amity between him and her and peace in the world, and she came and said, “My husband died,” she may marry; [or, if she said,] “My husband died,” she may be taken in yibum. [If there was] amity between him and her but war in the world, [or if there was] a conflict between him and her and peace in the world, and she came and said, “My husband died,” she is not believed. R' Yehudah says: She is never believed unless she comes weeping and with her clothes torn. They said to him: In either case she may marry.
Yevamos15: 2
בֵּית הִלֵּל אוֹמְרִים: לֹא שָׁמַעְנוּ אֶלָּא בְּבָאָה מִן הַקָּצִיר, וּבְאוֹתָהּ מְדִינָה, וּכְמַעֲשֶׂה שֶׁהָיָה. אָמְרוּ לָהֶן בֵּית שַׁמַּאי: אַחַת הַבָּאָה מִן הַקָּצִיר, וְאַחַת הַבָּאָה מִן הַזֵּיתִים, וְאַחַת הַבָּאָה מִן הַבָּצִיר, וְאַחַת הַבָּאָה מִמְּדִינָה לִמְדִינָה — לֹא דִבְּרוּ חֲכָמִים בַּקָּצִיר אֶלָּא בַהוֹוֶה. חָזְרוּ בֵית הִלֵּל לְהוֹרוֹת כְּבֵית שַׁמַּאי.
Beis Hillel said: We have not heard [this tradition] except [in the case] where she came from the harvest, and [from] the same country, as in the incident which occurred. Beis Shammai said to them: It is the same whether she came from harvesting grain, or [picking] olives, or picking grapes, or from one country to another -— the Sages mentioned the harvest only in recounting the actual incident. Beis Hillel recanted [and began] to rule like Beis Shammai.