Al Ula is an area of outstanding natural and historical significance in North-West Saudi Arabia. Located at the crossroads of continents, in a stony and sandy desert, it has been a fantastic meeting point for civilizations who left behind an abundant heritage. For centuries, Al Ula oasis has been a crossing point for caravans on the Incense trade route, which connected Asia, Africa and Europe. The oasis city has successively been ruled by Ancient North Arabian Kingdoms (Dedan then Lihyan), then by the Nabataeans who founded the ancient city of Hegra, then by the Roman Empire, before Muhammad’s arrival in 630 A.D. during his campaign against the Byzantine army. All these civilizations stamped the region with their unique culture, leaving exceptional archaeological sites and landscapes. The ECO-Seed project aims to comprehend the evolution of past ecosystems and plant dynamics in Al Ula region by using archaeo/palaeobotanical archives as a mean of revealing socio-economic, technical and environmental components. The project is two-fold. First, it focuses on the agrobiodiversity and the natural ecosystem variabilities through the study of plant remains (plant macro remains with seeds and charcoal, phytolites, pollen) recovered in anthropogenic and natural contexts. Secondly, it aims at characterising the origin(s) and growth conditions of plant through isotope geochemistry on selected modern and archaeological plants (cotton and date).