## 3 Results and Discussion  
### Diet Reconstruction  
Table 1 presents the \(\delta^{13}\)C\({}_{\text{col}}\) and \(\delta^{15}\)N\({}_{\text{col}}\) isotopic values of human bone collagen and \(\delta^{13}\)C\({}_{\text{ap}}\) isotopic values of human bone apatite of Agras. The results of radiocarbon dating for the three selected samples are also presented in the same table. These samples dated from 1000 to 800 BC, which corresponds to the Early Iron Age. For all of our samples, the atomic C:N ratio was between 2.9 and 3.5 (Table 1), while the collagen yield was over 1 wt %; thus, the collagen was well preserved [10; 69]. From Table 1 we observe that the \(\delta^{13}\)C\({}_{\text{col}}\) isotopic values ranged between \(-20.5\)% and \(-15.6\)%, with a mean value of \(-17\)% (s.d. 1%), while \(\delta^{15}\)N\({}_{\text{col}}\) isotopic values ranged from 6% to 11.1%, with a mean value of 8.8% (s.d. 1%). In Figure 2 we present our results compared with the ones from Edessa [3] and Alexandreia [2]. Additionally, we present some isotopic results of recent C3 and C4 plants (after the application of the Suess effect [2]), \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \begin{tabular}{c} **Sample’s** \\ **Code** \\ \end{tabular} & **Sex** & **Age** & \begin{tabular}{c} \(\delta^{13}\)C\({}_{\text{col}}\) \\ **(\%)** \\ **(v-PDB)** \\ \end{tabular} & \begin{tabular}{c} \(\delta^{13}\)C\({}_{\text{ap}}\) \\ **(\%)** \\ **(v-PDB)** \\ \end{tabular} & \begin{tabular}{c} \(\delta^{15}\)N\({}_{\text{col}}\) \\ **(\%)** \\ **(v-AIR)** \\ \end{tabular} & **C-N** & \
\begin{tabular}{c} \(\Delta^{13}\)C\({}_{\text{ap-col}}\) \\ **(\%)** \\ **(\%)** \\ \end{tabular} & **Date (BC)** &
\begin{tabular}{c} **Date Error** \\ **(Years)** \\ \end{tabular} \\ \hline T4b & female & 36–50 & \(-17.8\) & \(-13.2\) & 8 & 3.2 & 4.3 & - & \\ \hline T6b & male & 25–35 & \(-20.5\) & \(-14.9\) & 8.3 & 3.3 & 5.6 & 942–899 & 50 \\ \hline T7 & unknown & subadult & \(-15.6\) & - & 8.9 & 3.5 & - & - & \\ \hline T12b & unknown & subadult & \(-16.6\) & - & 11.1 & 2.9 & - & - & \\ \hline T13 & unknown & subadult & \(-18\) & - & 9.4 & 3.1 & - & 881–844 & 50 \\ \hline T14 & indeterminate & subadult & \(-16\) & - & 10 & 3 & - & - & \\ \hline T24 KT & female & 17–25 & \(-16\) & - & 6 & 3.1 & - & - & \\ \hline T24 BN & female & 36–50 & \(-16.5\) & - & 7.8 & 3.2 & - & - & \\ \hline T33 Ba & unknown & adult & \(-17.4\) & \(-12.3\) & 8.1 & 3 & 5.1 & - & \\ \hline T50b & female & 36–50 & \(-16\) & \(-12.2\) & 10.9 & 3.2 & 3.8 & 980–924 & 50 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: \(\delta^{13}\)C\({}_{\text{col}}\), \(\delta^{15}\)N\({}_{\text{col}}\), and \(\delta^{13}\)C\({}_{\text{ap}}\) isotopic values and radiocarbon dating from skeletal remains of Agras in the Early Iron Age period. ancient terrestrial animals [58]), and freshwater and marine fish [11] of the Macedonia region in North Greece. The isotopic values of \(\xi^{13}\)C for C3 plants ranged from \(-26.1\%\) to \(-23.4\%\), with a mean value of \(-24.9\%\) (s.d. \(0.9\%\)), for terrestrial animals from \(-21.6\%\) to \(-17.9\%\) with a mean value of \(-20\%\) (s.d. \(1\%\)), for freshwater fish from \(-20.8\%\) to \(-18.4\%\) with a mean value of \(-20\%\) (s.d. \(1\%\)), for C4 plants \(-10.6\%\) to \(-9.2\%\) with a mean value of \(-9.9\%\) (s.d. \(0.5\%\)), and for marine fish from \(-14.8\%\) to \(10.1\%\) with a mean value of \(-12\%\) (s.d. \(2\%\)). The isotopic values of \(\xi^{15}\)N for C3 plants from ranged \(-1.1\%\) to \(3.9\%\) with a mean value of \(2\%\) (s.d. \(1\%\)), for terrestrial animals from \(0.8\%\) to \(10.3\%\) with a mean value of \(5\%\) (s.d. \(3\%\)), for freshwater fishes from \(7.7\%\) to \(10.9\%\) with a mean value of \(9\%\) (s.d. \(2\%\)), for C4 plants from \(4\%\) to \(6\%\) with a mean value of \(5.2\%\) (s.d. \(0.7\%\)) and for marine fish from \(7.1\%\) to \(12.9\%\) with a mean value of \(10\%\) (s.d. \(2\%\)).