Geo-biological data complete historical and archaeological archives for documenting deltaic landscape transformations and human impact at Chilia-Lycostomo (Northern Danube delta)

This study confronts local environmental proxies (i.e., pollen, charcoal, paleofauna) with ancient sources documenting Kilia/Lycostomo Byzantine-Genoese settlement at the mouth of the northern Danube's distributary to reconstruct environmental changes which render difficult the localization of the Middle Age settlement. Historical data seem contradictory, while systematic archaeological research has been extremely difficult on the Chilia branch, the modern border between Romania and Ukraine. Yet, after the complete reevaluation of all the sources in relationship with their reconstructed paleoenvironments, we propose to locate the major Byzantine and Early Modern trading centre Lykostomion/Licostomo as well as Chilia at Kilija/New Chilia (now in Ukraine), on the Bugeac plateau, on the left bank of the Danube’s northern branch (itself called Chilia, former Lykostoma). Old Chilia (now in Romania), whose name was always taken as proof of the location of the famous historical city of Chilia, lacks archaeological traces of urban occupation before the 19^th-20^th century. In fact, this loess island in the delta, on the southern shore of the Chilia branch, has been used only for subsistence activities (fisheries, agriculture, husbandry) and for supporting the storage capacities of the main harbour of Lykostomion/Licostomo-Chilia, situated under the modern harbour of New Chilia. Besides texts and some scarce archaeological reports, this localisation is now supported by two sedimentary cores (PAR 1 and KIL 1) which allow the reconstruction of the Chilia branch progradation, with an absolute chronology based on ¹⁴C dates. Vegetation, charcoal and microfauna occurrence in the KIL 1 sediments of the last ca. 700 yrs are excellent proxies for the high-resolution study of the local deltaic dynamics under natural and human pressure. For the first time, they reveal information about the maritime and riverine milieux developing at the place where this trading hub was founded, the living conditions (food, housing, heating) of its inhabitants and the ecological changes related to their demographic fluctuations. Most interestingly, they show the environmental impact of the military conflicts and urban re-foundations, which occurred in the 13^th, 15^th and 18^th centuries at this major gate of SE Europe.