The women used to pray the dawn prayer with the Messenger of Allah ﷺ. When he gave the closing salutation, they would depart wrapped in their cloaks, unrecognizable due to the darkness before daybreak.
أخبرنا علي بن خشرم قال أنبأنا عيسى بن يونس عن الأوزاعي عن الزهري عن عروة
كان النساء يصلين مع رسول الله ﷺ الفجر فكان إذا سلم انصرفن متلفعات بمروطهن فلا يعرفن من الغلس
Bukhari transmitted it in "The Times of Prayer," chapter on the time of Fajr, hadith no. 578, and Muslim in "The Mosques," chapter on the recommendation of praying dawn prayer early in its time, etc., part 230/645, from the hadith of Zuhri through the same chain, and it is also in Kubra, hadith no. 1285.