Bulugh al-Maram #456

Narrated 'Aishah (RA): Allah's Messenger (ﷺ) did not offer more than eleven (voluntary) Rak'at during Ramadan nor during other than Ramadan. He offered four Rak'at - Do not ask about their beauty and length! (It is beyond description or imitation]. Again he would pray four Rak'at - Do not ask about their beauty and length! . Then he would pray three (Rak'at of Witr). 'Aishah (RA) said: "I said, O Allah's Messenger will you sleep before you pray Witr?" He said, "O 'Aishah my eyes sleep, but my heart does not sleep." .