"A woman came to the Prophet and asked him about that, and he said: 'During the Jahiliyyah, if her husband died, one of you would stay (in mourning) for a year, then she would throw a piece of dung then come out. Rather it (the mourning period) is four months and ten days, until the term prescribed is fulfilled.'" (Using translation from Nasāʾī 3541)
أَنَّ امْرَأَةً سَأَلَتْ أُمَّ سَلَمَةَ وَأَمَّ حَبِيبَةَ أَتَكْتَحِلُ فِي عِدَّتِهَا مِنْ وَفَاةِ زَوْجِهَا فَقَالَتْ أَتَتِ امْرَأَةٌ إِلَى النَّبِي ﷺ فَسَأَلْتُهُ عَنْ ذَلِكَ فَقَالَ «قَدْ كَانَتْ إِحْدَاكُنَّ فِي الْجَاهِلِيَّةِ إِذَا تُوُفِّيَ عَنْهَا زَوْجُهَا أَقَامَتْ سَنَةً ثُمَّ قَذَفَتْ وَرَاءَهَا بِبَعَرَةٍ ثُمَّ خَرَجَتْ وَإِنَّمَا هِيَ أَرْبَعَةُ أَشْهُرٍ وَعَشْرٌ حَتَّى يَنْقَضِيَ الْأَجَلُ»