However, Aristotle (384-322 BC) was already unsuccessfully engaged in "freeing the spirit of wine from wine". It is not certain when this was first achieved, but there are descriptions from the 2nd century B.C. The Roman author Pliny the Elder (23-79) surmised that there must be something combustible in the wine. The Aztecs in ancient Mexico mastered this art and made intoxicating drinks from agave (see under pulque). Tartars in the Gobi Desert produced the alcoholic drink "kumyss" from mare's milk and distilled it into "karakumyss" (milk brandy). When the Moors (Arabs) conquered Spain in the 8th century, they brought the art of distillation with them. This was mainly used in pharmacy and for the production of perfumed waters. Vessels made of different materials such as glass or ceramics, so-called alambics, were used for this purpose.