Cannabis is one of the most contentious and widely used drug plants in the world today. However, its history of use and the role that it played among peoples in the past is poorly understood. Historians and archaeologists have debated about ancient drug use for over a century, and cannabis has been the focus of this debate. Nevertheless, it is hard to wade through all the claims of ancient cannabis use to separate fact from myth. With modern scientific methods, it now possible for scholars to trace back these early uses. In this study, published in Science Advances in June of 2019, an international group of researchers examined the chemical signature on incense burners from ancient graves. The burners provided early evidence of cannabinoid residues and suggested that people were burning the plant as part of a funerary ritual. High levels of THC on these burners also indicated that the specific plants that they used had higher active compound levels than what is typical for wild populations.