Sefer Refuot (Hebrew: ספר רפואות, "The Book of Medicines"), also known as Sefer Asaph (English: /ˈsˈɛfərˈeɪ.sæf/ Ay-saf, Hebrew: ספר אסף, "The Book of Asaph" or "Asaf") , is the earliest-known medical book written in Hebrew.[1][2] Attributed or dedicated to Asaph the Physician (also known as Asaph ben Berechiah; possibly a Byzantine Jew;[3] or possibly identifiable with Asif ibn Barkhiya, a legendary mystical polymath vizier in Arabic folklore, associated with King Solomon) and one Yoḥanan ben Zabda, who may have lived in Byzantine Palestine or Mesopotamia between the 3rd and 6th Centuries CE (though this is very uncertain, and some have suggested that Asaph and Yoḥanan were both legendary sages in Jewish tradition, to whom the text was dedicated; not its literal authors).[4] The date of the text is uncertain, with most manuscripts coming from the late medieval era; though the lack of Arabian medical knowledge in the book implies it may have originally been written much earlier.