This article aims to show the transformation of the coast in the extreme northeast of the Iberian Peninsula. It is focused on the Ciutadella de Roses. Data were integrated from the digital elevation model (LIDAR), a geomorphological analysis, and lithostratigraphic and chronological correlations based on eight geological boreholes and twelve radiocarbon datings, along with historical data and archaeological remains found in the surroundings of the Ciutadella. This enabled a hypothesis to be established on the palaeolandscape around the site. The evolution of the shoreline from Ancient Greek times to the modern period is detailed, and evidence of its form at different chronological moments is presented. To sum up, the article defines the evolution of the palaeolandscape in the territory and links it to the historical evolution of the site. In addition, the evolution of the relationship between river courses, the sea and the sea level is explained.

The River Ter is one of the axes which, in a west-east direction, has historically articulated the population of the extreme north-east of the Iberian Peninsula. Although its upper, middle and part of the lower courses do not present any problems in its course, its mouth in the Mediterrane-an Sea has raised many questions due to the existence of two potential branches, one to the north that would flow into the Gulf of Roses and another to the south that would flow into the Bay of Pals. In 2016, an exhaustive documentary study on the potential southern branch provided exhaustive information on the existence of lake areas and their relationship with the settlement between the 9th and 11th centuries, but raised doubts about the existence of the river in the bay from Pals. Subsequently, between 2020 and 2022, geological studies have been carried out in this area which demonstrate the existence of the river in this area but with a variable course, with changes in the river channel (meandering, diffuse and braided), and with notable changes that conditioned the settlement of this sector of the coast and as was recorded in written documentation between the 9th and 11th centuries.