Emerald Tablet
The early Islamic period saw the establishment of some of the longest lived theoretical frameworks in alchemy and chemistry. The sulfur-mercury theory of metals, first attested in pseudo-Apollonius of Tyana's "Sirr al-khalīqa" ("The Secret of Creation", c. 750–850) and in the Arabic writings attributed to Jābir ibn Ḥayyān (written c. 850–950), would remain the basis of all theories of metallic composition until the eighteenth century. Likewise, the "Emerald Tablet", a compact and cryptic text that all later alchemists up to and including Isaac Newton (1642–1727) would regard as the foundation of their art, first occurs in the "Sirr al-khalīqa" and in one of the works attributed to Jābir.