I've been reading a lot recently about the early bronze age cultures of the Pontic-Caspian steppe and later. One thing that is apparent is that cannabis use was widespread and probably recreational at a very early date. It also seems as though the Greeks knew about its existence from fairly early on as well.
But other than occasional medical use, I can't find any evidence that cannabis was smoked recreationally in ancient Rome. Am I correct that it wasn't? Or do we simply not know?
If my initial assumption is correct, are there any reasonable guesses as to why it wasn't? The Greeks and Romans traded extensively with Crimea and points along the Black Sea coast, where they certainly would have come into regular contact with people who grew and smoked cannabis. In a society where trade in medicinals and narcotics was commercially important (e.g., silphium, opium), why wasn't this product exported when other drugs were, or grown locally? Or was it?
If Romans did smoke cannabis, we have no record of it. Eurasians don't actually seem to have smoked anything prior to the Columbian Exchange. If your sources indicate that bronze-age peoples were smoking cannabis, I'll stand corrected. I would however be dubious of any such claims, since marijuana smoking would be difficult to prove archaeologically. (And at least some archaeologists I know would be eager to jump from suggestive evidence to definitive statements about marijuana use.) Studies I've read have concluded that cannibus was generally chewed in the pre-modern world, although I haven't myself tested the medicinal or recreational effects of chewing marijuana.
Smoking as a technique seems to have confused early modern Europeans, and it took an especially for them to adopt. Columbus and his crews probably tried tobacco as early as 1493, but it didn't become a major European import until the 1610s. (Consider how many generations separate you from 1893, and we live longer than they did then!) Tobacco smoking spread to Africa at about the same time, perhaps along with the abortive efforts to establish tobacco plantations there.
The evidence suggests that the first experiments with smoking cannabis probably began in Africa (where it naturally grows) in the 1600s or shortly thereafter. The ancient Romans may have chewed, but they did not smoke, cannabis.
Check out the excellent book on tobacco, with some concluding asides on cannabis use, by Marcy Norton, Sacred Gifts, Profane Pleasures: A History of Tobacco and Chocolate in the Atlantic World (2008).
There are a couple of very good posts on this topic in this thread: http://www.reddit.com/r/AskHistorians/comments/2dvscw/herodotus_claimed_that_the_scythians_would_smoke/