The tablet states its author as Hermes Trismegistus ("Hermes the Thrice-Greatest"), a legendary Hellenistic combination of the Greek god Hermes and the ancient Egyptian god Thoth. Like most other works attributed to Hermes Trismegistus, the "Emerald Tablet" is very hard to date with any precision, but generally belongs to the late antique period (between c. 200 and c. 800). The oldest known source of the text is the "Sirr al-khalīqa wa-ṣanʿat al-ṭabīʿa" ("The Secret of Creation and the Art of Nature", also known as the "Kitāb al-ʿilal" or "The Book of Causes"), an encyclopedic work on natural philosophy falsely attributed to Apollonius of Tyana (c. 15–100, Arabic: Balīnūs or Balīnās). This book was compiled in Arabic in the late eighth or early ninth century, but it was most likely based on (much) older Greek and/or Syriac sources. In the frame story of the "Sirr al-khalīqa", Balīnūs tells his readers that he discovered the text in a vault below a statue of Hermes in Tyana, and that, inside the vault, an old corpse on a golden throne held the emerald tablet.