According to ThoughtCo., the bain-marie is named after Maria the Prophetess, also known as Mary the Jewess. She would have lived between the first and third centuries and would be the first known Western alchemist. Although none of her writings survive, she is often quoted by the 4th-century alchemist Zosimos of Panopolis, and she is universally credited with the inventions of the water bath and several other alchemical processes and equipment, including the distillation apparatus known as tribikos. , by Chemistry World. According to SciHi Blog, some consider tribikos a prototype of the modern pressure cooker.
As for the bain-marie, this heating bath named after its inventor is a valuable tool in the kitchen. As MasterClass explains, a bain-marie—which involves placing a smaller container (with ingredients) over or inside a larger container of hot water—allows the creation of sauces like Hollandaise, tempered chocolate and, according to Cook’s Illustrated, perfectly smooth cream. As Mary the Jewess must have used in her alchemical experiments, the heated water bath serves as a double boiler, one that gently heats items like chocolate or custard to a controlled temperature (via Wasserstrom).