 The earliest Syriac manuscript (British Library, Add MS 14528) is usually dated to the 6th century, although a date as late as the 8th century has been argued for.In the 20th century, several later Syriac manuscripts from the 13th–17th centuries came to light.One of these identifies the compiler as a certain Ambrosius, a contemporary of an emperor Valentinian, probably Valentinian III, but this information is not reliable.