The Messenger of Allah (ﷺ) would say the Fajr prayer after which the women would depart wrapped up their woolen garments, being unrecognizable because of the darkness before dawn.
Sunan Abi Dawud Book 2, Hadith 33
← Previous Hadith We observed the prayer after nightfall with the Messenger of Allah (ﷺ), and he did not come out till about half the night had passed. He then said: Take your places. We then took our places. Then he said: The people have prayed and gone to bed, but you are still engaged in prayer as long as you wait for the prayer. Were it not for the weakness of the weak and for the sickness of the sick. I would delay this prayer till half the night had gone.

Sunan Abi Dawud Book 2, Hadith 32 Next Hadith → Offer Fajr prayer at dawn, for it is most productive of rewards to you or most productive of reward.

Sunan Abi Dawud Book 2, Hadith 34