The Emerald Tablet of Thoth

Traditional Western alchemists hold that Alchemy originated with Thoth in ancient Egypt (Khemet).

The "Emerald Tablet" is purported to be written by Thoth (Hermes Trismegistus) and considered the most important alchemical declaration ever found in the Western World.

Translations of the text were posted in the workshops of ancient alchemists and can be observed in images of those era.

Most modern alchemists also display these words in their work areas.
Sir Isaac Newton's Version Taken from his Personal notes on Alchemy.

Other Sources

Other sources of ancient Alchemical texts are located in the Mahabharata, The Kabbalistic parts of the Torah, The TAO from China which uses the writings of the book called "The Secret Of The Golden Flower".