Ya'la bin Mamlak relates: I asked Sayyidah Umm Salamah (may Allah be pleased with her) about the night prayer of the Messenger of Allah (peace and blessings be upon him), and she said: "He (peace and blessings be upon him) would pray Isha, then glorify Allah as much as Allah willed, then sleep, then wake up after as long as he had slept, then sleep and get up again; and his (peace and blessings be upon him) prayer remained like this until the morning."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20279