Abstract: We present the oldest mortar manufactured and used in Europe, a remarkable artifact recovered from the lower level of the prehistoric site of Martinarri (Treviño, northern Spain), dating to the end of the Upper Pleistocene. A multidisciplinary approach has been applied to study the tool, including analyses of use-wear, phytoliths, pollen, and charcoal. Ethnographic parallels and comparisons with other archaeological contexts have also been explored, suggesting that it was intensively used for processing vegetables, probably acorns, though other possibilities cannot be excluded. This study highlights that the consumption of wild plants was undoubtedly more prevalent in Late Palaeolithic Europe than previously recognised, largely due to a scarcity of direct evidence. The diet of the Martinarri community was supplemented by hunted game, as indicated by abundant faunal remains, and accompanied by other domestic activities such as leatherworking and flint knapping. As part of an overall strategy, the human community occupied Martinarri on numerous occasions, even preparing relatively complex structures, as well as a series of other geographically close deposits: the objective was the comprehensive exploitation of the region.
