8th - 13th Century
See also Early Alchemy for discussion of prior alchemical period (2nd to 7th Century).
MEDIEVAL MANUSCRIPTS contained many practical recipes and showed the state of chemical knowledge in Europe from the 8th to the 13th century.
..."no one of them contributed anything of importance either of facts or theories to the knowledge of their predecessors"... but "by their extensive summarizing of the authorities existing in their time and by the weight of their authority they did much to make accessible the accumulation of the knowledge of the past and to revivify and popularize the study of science." ---Stillman