The Turba Philosophorum

" The Turba philosophorum or Peat of the Philosophers (in the sense of Assembly of Philosophers) is one of the first and most famous texts of medieval Western alchemy. There are two versions. A Latin of the thirteenth century, the Turba Philosphorum proper, and which is in fact the translation of an Arabic treatise of the tenth century. And one in French, called Turba Gallica, from the 15th century, a probable translation of an original in Castilian from the 13th century.
It is a pseudepigraphic treatise presented as the report of an assembly of pre-Socratic Greek philosophers under the presidency of Pythagoras. Appended to the versions is another text, the Vision of Arislée or Vision d'Arisleus."