**6. Discussion**

#### *6.1. Burials and the Classification of Social Status during the Late Shang Dynasty*

In order to determine a possible correlation between social status and dietary differences at the Xiaohucun site, it is important to understand how social status may have influenced the tomb type and value. In ancient China, tombs and burials can be graded and valued based on the human labor costs and materials used for construction, the size and shape of the structure, as well as the number and type of graves goods reflecting symbols of power and wealth interred with individuals [55,71]. Since the shapes of all the late Shang Dynasty burials at Xiaohucun were rectangular, the preliminary grading scale of the 12 tombs was classified by number of coffins, tomb depth, and size, and by the presence of bronze funerary objects and this information is listed in Table 1 and plotted in Figure 4. Tomb sizes ranged from 1.54 m<sup>2</sup> to 7.35 m<sup>2</sup> (4.25 ± 1.9 m2, n = 12), the burial depth was between 0.66 m to 4.3 m (1.93 ± 1.1 m, n = 12), which could sugges<sup>t</sup> that the cemetery was under a type of burial managemen<sup>t</sup> based on social hierarchy. More importantly, the burial depth and tomb size were found to have a linear correlation (R<sup>2</sup> = 0.67, *p* = 0.001) with clear differences between the number of coffins used and whether a burial contained bronze vessels.

**Figure 4.** Plot of burial depth (m) vs. tomb size (m2) for individuals buried in different coffin types with and without bronze funerary vessels at the Xiaohucun site, Henan Province, China.

In addition, past studies developed a specific classification system for Shang Dynasty tombs [3,71], where they can be divided into three different categories (A, B, C) with seven subdivisions (Aa, Ab, Ac, Ba, Bb, Bc, C) (Table 4). Using this system, seven of the tombs (M8, M52, M27, M24, M105, M30, M90) at Xiaohucun are assigned to type Bb. Thus, the owners of these seven tombs are presumed to be junior nobility: six had double coffins and all seven were buried with bronze funerary vessels. Four other tombs (M47, M46, M116, M89) were matched to the Bc category, an indication that the occupants were common people (Table 4). A single tomb (M39) gave somewhat conflicting results. The tomb size was large (3.92 m2) indicating the owner could have been a noble, but the individual was found to be buried without coffins or bronze funerary objects which is an indication this individual was of the lower class (Table 4). It is important to recognize that these classifications are based on information from the royal Shang capital at Anyang and may not be directly applicable at Xiaohucun. However, their use here provides an important starting point from which to explore the relationship between dietary differences and social status during the late Shang Dynasty.

#### *6.2. Diet and Social Status*

No difference is observed between the δ13C results of the perceived elites (n = 7) buried with bronze vessels (−9.1 ± 2.8%) and the individuals (n = 5) buried without bronze vessels (−8.2 ± 0.7%), and this indicates that all classes of the population relied heavily on a millet based diet (Figure 5a). However, individuals buried with bronze vessels (10.3 ± 1.6%) were found to have significantly higher δ15N values (one-way ANOVA; *p* = 0.015) compared to individuals buried without bronze vessels (8.0 ± 0.9%). This finding suggests that the elite during the late Shang Dynasty were consuming a diet with possibly more animal protein or fish than the commoners. Subtle similar patterns have also been noted at the sites of Xipo (ca. 4000–3300 BC) and Qianzhangda (ca. 1000 BC) [54,56]. In particular, at Qianzhangda, a tomb owner associated with a larger grave was found to have a higher δ<sup>15</sup> N result compared to the other tomb owners with smaller sized burials, and tomb owners were also found to have higher δ15N results than sacrificed individuals. Zhang et al. [56] concluded that these elevated nitrogen results of the elites with larger tombs were related to increased meat consumption. However, the results presented here are the first to sugges<sup>t</sup> a possible direct isotopic link between diet and social status at a middle Shang Dynasty site from the Central Plains of China.

**Table 4.** Classification of social status for burials from the Shang and Zhou Dynasties. Note: Information is referenced from IA CASS [3].


**Figure 5.** (**a**) δ13C and δ15N results showing the di fferences between individuals buried with and without bronze vessels at the Xiaohucun site, Henan Province, China. The δ15N results are statistically significant (one-way ANOVA; *p* = 0.015); (**b**) δ13C and δ15N results for individuals buried in a double, single, or without a co ffin at the Xiaohucun site, Henan Province, China. The δ15N results were not found to be statistically significant using one-way ANOVA tests (double vs. single, *p* = 0.288; double vs. none, *p* = 0.095).

In addition, the isotopic values of the tombs were examined by co ffin type: double co ffin, single co ffin, and no co ffin (Figure 5b). No di fferences in δ13C were observed for the double (−9.1 ± 3.1%), single (−8.5 ± 0.9%), and no co ffin (−8.2 ± 0.7%) burials. Yet again, there were di fferences in the δ<sup>15</sup> N values: double (10.2 ± 1.7%) > single (8.8 ± 1.8%) > no co ffin (8.0 ± 1.3%) suggesting that possible di fferences in animal protein consumption were present during the lifetime of these individuals. However, while these results are interesting, they must be viewed with the utmost caution as they were not found to be statistically significant using one-way ANOVA tests (double vs. single co ffins, *p* = 0.288; double vs. no co ffins, *p* = 0.095).

We further examined the isotopic results of the burials in relation to the number of co ffins and tomb sizes since a larger size might equate to higher social status based on the increased labor costs of construction. This permitted an investigation of possible dietary di fferences within the same social class; specifically did individuals with larger tombs have diets di fferent from individuals with smaller tombs? As with the previous measures of status, the δ13C values show little correlation with the size of the tombs, and the entire population, regardless of status, was focused on the consumption of millet (Figure 6a). The δ15N results of the individuals with a single or no co ffin burial show little

correlation with tomb size (Figure 6b). In contrast, a significant positive linear correlation (R<sup>2</sup> = 0.84) is observed for the δ15N values between the individuals buried in two coffins and the tomb size. This is possible evidence that owners that were wealthy/powerful enough to build bigger tombs had diets that contained increasing amount of animal products, and the largest tomb (M8) had an occupant that consumed the most animal protein (Figure 6b). While these findings are intriguing and agree with the historical accounts described in Zhou Li "周礼" (Rites of the Zhou Dynasty by Zhou Gong "周公", ca. 1100 BC [88]) and Chunqiu Gongyang Zhuan "春秋公羊传" (Gongyang's Commentary on Spring and Autumn Annals by Gongyang Gao "公羊高", ca. 507 BC [89]) extreme caution is warranted as the sample size is unfortunately small.

**Figure 6.** (**a**) δ13C results vs. tomb size (m2) for individuals buried in a double, single, or without a coffin at the Xiaohucun site, Henan Province, China; (**b**) δ15N results vs. tomb size (m2) for individuals buried in a double, single, or without a coffin at the Xiaohucun site, Henan Province, China.

It is noteworthy that the δ15N values of some burials did not correlate with the corresponding tomb size although a general relationship between the two variables was observed as mentioned above. The reasons for this are complex and unknown but could be related to the slow turnover rate of bone collagen which averages the general dietary protein isotope signatures of the last decades of life [25,26]. If an individual fell on financial or social misfortune and their social standing was diminished during the later years of their life, this could account for a difference in the social status of their burial vs. Their lifetime diet. For example, the δ15N result (10.8%) of M90 was high and he was buried with some bronze funerary objects suggesting a possible elevated social standing during life, but the small size of his tomb (3.95 m2), shallow burial depth (0.66 m), and the fact that he was only buried in a single coffin could imply that his social status or personal fortunes declined later in life. In addition, the reverse scenario could be envisioned for the M30 burial. This individual had a δ13C value (−15.2%) which was radically different that the rest of the population and the lowest δ15N value (7.6%) of all the perceived elite burials. This is possible evidence that this person was a commoner that immigrated to the Xiaohucun community, and that this individual was not born into elite status but acquired it later in life, possibly though marriage, accumulation of wealth, or behavior (bravery in battle). However, all of these possibilities are speculative scenarios and addition research is necessary (ancient DNA, sulfur and strontium stable isotope ratios, etc.) to better understand these patterns, and variables such as age and sex should also be considered in future studies that examine Shang Dynasty sites for social stratification with stable isotope ratio analysis.
