Alchemy, which means art of transmuting metals in Greek, is the medieval chemical science and speculative philosophy that aimed to change basic metals like lead or copper into silver or gold, as well as discover a cure for disease and a method of extending life. According to the accounts of the Gnostic Christian writer Zosimos of Panopolis and other authors in the Greek alchemist tradition, Mary or Maria the Jewess, also known as Mary the Prophetess or Maria Prophetissima, who lived in Alexandria between the first and third centuries AD and invented several kinds of chemical apparatus that were used for centuries after that, was the first known alchemist in history and is considered to be the first true alchemist of the Western world. While describing her several experiments and instruments in his works, Zosimos almost always mentioned Mary as one of the sages, having lived in the past.

However, George Syncellus, a Byzantine chronologist of the 8th century, mentioned her as a teacher of Democritus, an Ancient Greek pre-Socratic philosopher from Abdera, a town on the coast of Thrace in ancient Greece, who met her in Memphis, Egypt, during the time of Pericles. Apart from that, the 10th century Muslim Bibliographer Ibn al-Nadim cited Mary in his Kitab al-Fihrist as one of the 52 most famous alchemists, who could prepare caput mortuum, a purple pigment of haematite iron oxide, popular for painting the robes of religious figures and important personages.

Epiphanius, the bishop of Salamis, Cyprus, at the end of the 4th century and considered a saint, mentioned two writings by Mary the Jewess, Great Questions and Small Questions, where he credited her with a vision of Jesus.

Apart from that, the name of Mary is also mentioned in Arabic writings, where she is said to be a contemporary of both Jesus, having carried the infant Jesus in her arms and also of Ostanes, a Persian brother-in-law of Xerxes the Great, the fourth King of Kings of the Achaemenid Empire, from 486 BC until his assassination in 465 BC.

Although none of Mary's writings have survived, several cryptic alchemical precepts have been attributed to Mary and some quotations credited to her are found in hermetic writings, among which some notable are found in The Dialogue of Mary and Aros on the Magistery of Hermes, an extract made by an anonymous Christian philosopher. Some operations described in that document, such as leukosis or whitening and xanthosis or yellowing, would later become the basis of alchemy and for the first time, the document described acid salt and other acids. But Alchemy is not chemistry and many of Mary’s surviving fragments are mysterious in the extreme, which include the recipes for making gold from plants.

Along with Agathodaemon, Pseudo-Democritus and Hermes Trismegistus, Mary was mentioned by Zosimos of Panopolis in his descriptions of certain devices, such as the Tribikos, Kerotakis and the Bain-Marie.

The tribikos was a kind of beaker or alembic with three arms that was used to purify a substance by distillation. Although it is not known whether Mary invented it, Zosimos credited the first description of the instrument to Mary and mentioned that Mary in her writings recommended that the copper or bronze used to make the tubes, should have the thickness of a frying pan and the joints between the tubes and the still-head should be sealed with flour paste.

Nevertheless, the kerotakis is an airtight container with a sheet of copper upon its upper side, used in alchemy to heat substances and to collect vapors. The term hermetically sealed in the hermetic arts has originated from the use of such sealed containers. The device was said to be a replication of the process of the formation of gold that was occurring in the bowels of the earth. Much later, the device was modified by the German chemist Franz von Soxhlet in 1879 to create the Soxhlet extractor, named after him.

However, Mary's name survives in her invention of the Bain-Marie, also known as Mary's Bath, a term used for both a process and a device, which limits the maximum temperature of a container and its contents to the boiling point of a separate liquid, which is something like a double boiler. The term, extensively used in chemical processes for which a gentle heat is necessary, was introduced by Arnold of Villanova in the 14th century. Even today, the term Bain-Marie is still used in cooking.