Funny and interesting read to help relax the trolling wave caused by the first early Hittite samples:
Cannabis is indigenous to Europe and cultivation began during the Copper or Bronze age: a probabilistic synthesis of fossil pollen studies, by McPartland, Guy, & Hegman, Vegetation History and Archaeobotany (2018).
Abstract (emphasis mine):
Conventional wisdom states Cannabis sativa originated in Asia and its dispersal to Europe depended upon human transport. Various Neolithic or Bronze age groups have been named as pioneer cultivators. These theses were tested by examining fossil pollen studies (FPSs), obtained from the European Pollen Database. Many FPSs report Cannabis or Humulus (C/H) with collective names (e.g. Cannabis/Humulus or Cannabaceae). To dissect these aggregate data, we used ecological proxies to differentiate C/H pollen, as follows: unknown C/H pollen that appeared in a pollen assemblage suggestive of steppe (Poaceae, Artemisia, Chenopodiaceae) we interpreted as wild-type Cannabis. C/H pollen in a mesophytic forest assemblage (Alnus, Salix, Populus) we interpreted as Humulus. C/H pollen curves that upsurged and appeared de novo alongside crop pollen grains we interpreted as cultivated hemp. FPSs were mapped and compared to the territories of archaeological cultures. We analysed 479 FPSs from the Holocene/Late Glacial, plus 36 FPSs from older strata. The results showed C/H pollen consistent with wild-type C. sativa in steppe and dry tundra landscapes throughout Europe during the early Holocene, Late Glacial, and previous glaciations. During the warm and wet Holocene Climactic Optimum, forests replaced steppe, and Humulus dominated. Cannabis retreated to steppe refugia. C/H pollen consistent with cultivated hemp first appeared in the Pontic-Caspian steppe refugium. GIS mapping linked cultivation with the Copper age Varna/Gumelniţa culture, and the Bronze age Yamnaya and Terramara cultures. An Iron age steppe culture, the Scythians, likely introduced hemp cultivation to Celtic and Proto-Slavic cultures.
Interesting excerpts (modified to make them more readable):
C. sativa during the Copper age
We compared the territories of Copper age cultures with locations of C–H pollen consistent with Cannabis in Fig. 5. This suggests that two Copper age cultures had the potential to domesticate wild-type C. sativa: the Greek Chalcolithic, and the Cucuteni-Tripolye culture. C–H pollen consistent with cultivated Cannabis occurred at one site in Bulgaria. This site may correspond to the Varna culture or Gumelniţa culture. However, pollen at five other Varna and Gumelniţa sites was interpreted as Humulus, or undetermined C/H. Archaeological studies of Gumelniţa and Cucuteni-Tripolye sites have found C. sativa seeds and less-robust evidence—pottery seed impressions (Clarke and Merlin 2013; Long et al. 2017; McPartland and Hegman 2017).
C. sativa during the Bronze age
Eight Bronze age cultures had potential: C–H pollen consistent with wild-type Cannabis in Fig. 6 appeared within the boundaries of several Bronze age cultures. These include the Netted Ware culture, Ezero culture, Yamnaya culture, Corded Ware culture, Bell-Beaker culture, Terramara culture, Aegean Bronze age, and Mycenaean Greece. C–H pollen interpreted as cultivated C. sativa appeared in four studies: One study in Yamnaya territory agrees with archaeological studies, which have recovered C. sativa seeds or pottery seed impressions (Clarke and Merlin 2013; Long et al. 2017; McPartland and Hegman 2017). Two study sites are associated with the Terramara culture. However, pollen in 11 other studies at Terramara sites suggested Humulus or indeterminate C/H pollen. One FPS in France was likely contaminated by taphonomic processes, as admitted by its authors.
Scythian contacts with Celts and Balto-Slavs
The Scythians impacted deeply on the Celts, in the realms of art, animal husbandry, military strategy, language, and even clothing. The oldest evidence of Scythian–Celtic interactions that we could find was a 7th century bce burial in Bulgaria, which combined elements of Scythian culture along with a Hallstatt vessel (Braund 2015). Scythian artifacts in Hallstatt-occupied Hungary first appear around 550 bce (Bartosiewicz and Gál 2010). A Hallstatt burial at Vix in France from 525 bce contains items and motifs inspired by Scythian culture (Megaw 1966). These data collectively suggest a conservative date of 550 bce as the terminus post quem for Scythian contact with the Celts. Only three sites in Celtic territory showed pollen signals consistent with hemp cultivation prior to 550 bce. To wit, the oldest ones had problems with dating. In contrast, 28 FPSs in Celtic territory showed pollen signals of hemp cultivation arising post-550 bce, after their contact with the Scythians.
The Scythians also impacted Proto-Slavic cultures. The Scythians left a trail of burned-out settlements built by the Proto-Slavic Lusatian culture around 600 bce (Bukowski 1977). A horde of Scythian artifacts found at Witaszkowo in Lusatia dates to 550 bce (Furtwängler 1883). Only two pre-550 bce sites in Slavic/Baltic territory showed signals consistent with hemp cultivation, and they occurred in the southeast, towards the Scythian homeland. Ralska-Jasiewiczowa and van Geel (1998) linked the appearance of Cannabis pollen in Poland with Scythian incursions. The Scythians appear to be responsible for the spread of Cannabis amongst several Iron age European cultures.
There you have it, the long-sought Yamna – Corded Ware cultural connection. Finno-Ugric peoples liked it wild, though ;-)