Al-Qasim narrates from Sayyidah Aishah (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) used to pray ten rak'ahs at night, one rak'ah of witr and two rak'ahs of Fajr; these made thirteen rak'ahs in all.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4676