NEW PAPER! https://doi.org/10.1098/rsos.230741 Whaling in Europe is known to have been performed for hundreds of years. Many northern and western European countries performed whaling, especially in Arctic waters around Svalbard and Greenland, since the seventeenth century. But the targets and practices of pre-industrial whaling in Europe remain poorly understood. Now, a new study published in the journal Royal Society Open Science suggests these early whaling activities were widespread and had a significant impact of whale populations in European waters. I led this group endevour and analyzed 719 archaeological bones from all over northern and western Europe and examined the preserved protein to identify the species. Collagen tends to have a different structure for most mammals and is useful for species identification purposes. We discovered that many bones belonged to two whale species no longer present in European waters. Over 300 whale bone specimens are thought to derive from the North Atlantic right whale. This large whale species can currently only be found on the North American side of the North Atlantic, but these bones indicate that the species was previously widely targeted in European waters. This species is critically endangered and only 300-400 individuals remain. The second species that was encountered in high numbers is the grey whale. Just over 100 whale bones were identified as belonging to this species. This species is now extinct in the North Atlantic and can currently only be found in the North Pacific. Both the North Atlantic right whale and the grey whale are highly coastal species. This put them within the reach of medieval whalers such as the Basques, northern Spaniards, Normans, Flemish, and Scandinavians. Medieval whaling probably played a significant role in the ultimate disappearance of these animals from European waters. Additionally, we suggests that whaling was conducted even longer ago. The Late Stone Age Vlaardingen-Culture, present in the western part of the Netherlands around 3500-2500 BCE, might have targeted the grey whale. Grey whale bones have been found at various archaeological sites pertaining to the Vlaardingen-Culture, which might signify one of the oldest whaling traditions in Europe. Looking into the past provides a better understanding of where the North Atlantic right whale and grey whale were once present, and what their migration patterns were. Over the past two decades at least three grey whale individuals have re-entered the North Atlantic, presumably through the northwest Passage (which is ice free for longer periods of time due to ongoing climate change) from the North Pacific. Understanding how early whaling activities impacted European whale populations is vital for conservation efforts. If a return to European waters occurs we can potentially better safeguard the grey whale by knowing where they once thrived. This study was funded by the European Union Marie Skłodowska-Curie Actions, KNAW Ecology grant, and the European Research Council (ERC) Synergy Project 4-OCEANS.