## 3 Results and Discussion
### Climatic Conditions and Mobility
However, it is unlikely that every individual in Edessa was drinking water from different reservoirs within the city and that the majority of the individuals drank water from very high altitudes, i.e., 1000 m (only the springs of 1100 m had oxygen isotope values of \(-\)9.5%), given that a spring existed (at 400-500 m altitude, with an oxygen isotope value of \(-\)8%) near the city. Probably, this observed variability in consumed water could be attributed to the existence of nonlocal individuals. Hence, these out-of-range individuals from Edessa must be examined separately. The isotopic signature recorded in the permanent teeth reflects the water consumed early in life, while that recorded in the bones reflects the water consumed during the last 10-20 years of life. Therefore, the oxygen values of enamel show the climate in the region they were born, while the oxygen values of apatite show the climate in the region where the individual lived before his/her death. In Figure 7 we present the results of oxygen apatite and enamel for each sample. Figure 6: The differences in \(\delta^{18}\)O\({}_{\text{w}}\) isotopic values of ingested water between individuals in (**a**) Agras and (**b**) Edessa. The red dashed lines indicate the isotopic range of the waters of the area. In (**b**) the filled blue circles indicate men and the open triangles indicate women. Two of the individuals (E/T23 and E/T9) were identified as nonlocals based on both their teeth enamel and apatite values. These two individuals appear to have been born or lived in a lower-altitude region with low \(\delta^{18}\)O\({}_{w}\) values, at least during their early childhood, after which [PERSON] migrated from this area to an even lower-altitude and warmer area at Edessa, while [PERSON] remained in the same place. Two individuals (E/T40b and E/T32) were identified as nonlocal based on their bone oxygen values, while their isotopic values fell within the local range based on their teeth oxygen values, indicating that they migrated from Edessa to a warmer climate as adults (Figure 6). Three individuals appear to have had different histories: E/T29, E/T4B and E/T20B were identified as nonlocal based on their \(\delta^{18}\)Oap values, suggesting that they could have been born in Edessa, but they migrated and lived in a place with lower \(\delta^{18}\)O, colder than Edessa, and then moved to Edessa before their death. Two individuals, one male, E/T27B, and one female, E/T25, appear to have been born in warmer places than Edessa, migrated to a colder place and then returned to Edessa before their death. Finally, E/T35 appeared to be local to Edessa as both teeth and bone oxygen fell within the expected range. Furthermore, regardless of the studied period, we observed that Agras oxygen isotopic values were similar to the values of Edessa, thus we do not expect climatic differences between these two periods. In contrast, the \(\delta^{18}\)O\({}_{w}\) isotopic values were more negative compared with the ones measured at modern Edessa springs [19], which range between \(-9.5\%\) and \(-7\%\). As more negative oxygen isotope values are present in colder climates, we assume that Agras and Edessa were colder and drier in ancient years than today. We noticed that these more negative oxygen values were not seasonal as people were drinking water from local springs. Springs have a low seasonal effect on their oxygen isotope values, since mechanisms like water-rock and water-soil interactions, water flow, mixing and evaporation dominate for \(\delta^{18}\)O\(\%\) values. Thus, the spring water consumed by individuals is different from the local meteoric water, which is highly affected by seasonality. Indeed, the oxygen isotopic values of the ingested water is in accordance with palaeoclimatic data [15] that indicate a much colder period of drier conditions. The pronounced drier and colder conditions of the region also coincide with other records from the Mediterranean that were reported by [PERSON] [89; 90] and [PERSON] [91].