ORG-ID aims at broadening the dating options for archaeological sites by means of the AMS 14C dating of plant temper preserved in pottery. Establishing the chronology of archaeological sites in Belgium is often challenging, due to the poor preservation of organic material. When organic remains are preserved, their association with the human activities is not always clear and/or they may yield altered dates due to an old wood or reservoir effect. Pottery, however, is a common find on archaeological sites and it has a direct chronological link with the human activities. In Belgium, and by extension, NW Europe, plant material has been added as a tempering agent to ceramics from the Neolithic period to the early Middle Ages (c. 5000 BC – 800 AD). It is preserved as charred remains inside the pottery and can be extracted for AMS 14C dating. However, up to now, this dating method has rarely been attempted in NW Europe. ORG-ID will explore the chronological potential of plant temper in pottery from archaeological sites dating from the Neolithic to medieval period, using Belgian sites as an example. The plant species that were used as temper in this pottery will be identified using a combination of petrographic analysis, X-ray μCT and SEM analysis. This will provide interesting insights into the pottery technology, and will inform us about the chronological potential of the plant temper, as only terrestrial plants would yield reliable dates. In addition, we will test different methods for the extraction of plant temper from the pottery, to optimise the sampling for AMS 14C dating, and for the chemical pre-treatment of this material prior to AMS 14C dating, in search for the most effective methodology. Finally, the reliability of the plant temper dates will be evaluated by comparing them to available, reliable dates on other (organic) materials from the same sites. Based on the results of a recent pilot study, we are confident in the feasibility of this project. It will open up new possibilities to date archaeological sites in Belgium, including sites for which other datable materials are largely lacking. The methodology developed for plant temper dating in this project can also be applied to archaeological sites in other countries.