**1. Introduction**

Ancient China was a complex and highly socially stratified society [1–4]. Vast disparities existed between the nobility and the common people in areas such as rights, ownerships, diet, customs, behavior etc. These di fferences were chronicled in various historical works such as: Li Ji " 礼 记" which described how criminal law did not apply to senior o fficials and that etiquette did not apply to common people [5]. This social hierarchy of the living was also extended to the treatment of the dead, and the phrase: "Honor the dead as the living", recorded by Xun Zi " 荀 子", was and still is an important concept that is intertwined through the fabric of Chinese society [6,7]. Social status could also be maintained in the afterlife by the size and the scale of the tomb, and the quantity and quality of the grave goods interred with an individual [8–12].

Stable isotope ratio analysis has been successfully applied to examine dietary patterns in past populations from many societies across the globe [13–24]. Isotopic results of bone collagen primarily reflect the protein component of the diet averaged over the entire lifetime of an individual, including a large

portion of collagen synthesized during later childhood and adolescence [25,26]. Briefly, stable isotope ratios are defined as the ratio of the heavier to the lighter isotope (e.g., 13 C/12C or 15 N/14N) and are compared in terms of δvalues in parts per 1000 or "per mil" (%) in relation to internationally defined standards for carbon (Vienna Pee Dee Belemnite, VPDB) and nitrogen (ambient inhalable reservoir, AIR) [27]. In Chinese archaeological research, δ13C measurements of human and animal collagen allow for an examination of the contribution of C3 (rice, wheat, barley etc.) and C4 foods (millets) to the diet. These studies have been vital for the reconstruction of a coarse time scale for the spread of different forms of agriculture in China [28–35] and for understanding animal husbandry practices [36–39]. The δ15N results can be used as an estimation of the trophic level of a human or animal in a foodweb and are based on the observation of an increase of about 3%–5% from the food to the consumer tissue [14,40,41]. Thus, levels of animal protein consumption can be examined with nitrogen isotope ratios. Modern human studies have found higher δ15N values in omnivores compared to vegeterians and vegans [42,43]. However, an in-depth discussion on the intricacies of stable isotope ratios to reconstruct past diets is beyond the focus of this paper and the reader should consult the reviews of Katzenberg [44], Ambrose and Krigbaum [45], and Lee-Throp [46].

Increasingly, this technique is used to directly document dietary di fferences between social classes, e.g., elites vs. common people [47–52], and the reader is directed to consult Twiss [53] for a review of food and social diversity in archaeological and isotopic research. However, relatively little research has focused on the use of stable isotope ratios to directly determine dietary di fferences related to social status in China [54–58]. It is widely accepted that the Shang Dynasty (1600–1046 BC) is an early Chinese era based on abundant written records and the rich archaeological evidence [59–64]. Thus, this period is an extremely important phase in the development of the earliest Chinese civilization, and the formation of the ritual systems of power, class, and hierarchy [3]. Here, we present results of a small pilot study that examines dietary patterns related to social status for burials that date to the late Shang Dynasty (ca. 1250–1046 BC). Humans (n = 12) from the site of Xiaohucun and animals (n = 11) from the nearby contemporaneous site of Guandimiao in Henan Province were available for study due to a rescue excavation. The results of this research will be the focus of this work [65].

#### **2. Background of Ritual Systems in Ancient China**

China has a long and vibrant tradition of organized rituals and hierarchy, and this is especially evident for dining practices as well as the type of food consumed [66–70]. A separate system of dining was very popular for the elite members of society. At dinner, individuals kneeled next to an Aiji "案 基" (a kind of little table) and a selection of tableware was placed next to each person for holding cereals, meat, water, beverages, and liquor. The type, quality, and number of the dishes served were determined by the status and the age of the diners. Elders and people of high social status had the right to use more bronze vessels [69,71]. According to written accounts and archaeological data, the most important tableware in China were Ding " 鼎" (an ancient vessel for cooking or holding meat) and Gui "簋" (an ancient vessel for holding grains), and a combination of both is the Chinese characters for banquet " 飨 宴", which was a symbol associated with nobility [72] (Figure 1). The number of Ding and Gui that a person could use in life was consistent with their social status, and this was also reflected in the combination of these items that were buried with the dead (Table 1). In addition, the consumption of meat was a privilege of the nobility and elders of a family before the Qin Dynasty (Table 1). The work Li Ji " 礼 记" recorded that "If there is not an important reason, the princes shouldn't kill cattle to eat, senior o fficials shouldn't kill sheep to eat, junior o fficers shouldn't kill dogs and pigs to eat, and the common people should not eat meat [5]. Thus, meat was a luxury dietary item that was generally reserved for elites and only for special occasions such as festivals or banquets. In addition, analysis of ceramics from the early Shang Dynasty site of Yanshi determined di fferent structures and behaviors of dining between the palace elites and the individuals that made pottery [73]. Reinhart determined that the Yanshi elites engaged in large-scale exclusionary feasting in contrast to the simpler and home cooked meals of the potters.

**Figure 1.** Bronze ritual vessels discovered in tomb M22 of Xiaohucun site (**a** = Ding, **b** = Gui, **c** = All bronze grave goods).

There were also strict rules for the maintenance of social status for the deceased in ancient China. Tomb size and burial depth (representing wealth and labor consumption) and the quantity and quality of the coffins used were some of the most important criteria reflecting social status (Table 1) [74,75]. The writings of Xun Zi " 荀 子" described that the number of coffins used for the Emperor was seven, for a prince was five, for senior nobility was three, and for junior nobility was two [6]. Furthermore, there were strict codes for the materials, size, thickness, as well as the internal and external decoration patterns of coffins, and this was related to hierarchy in Chinese society (Table 1). In addition, the type and quality of grave goods was an important manifestation of the status of the deceased. At least from the Zhou Dynasties, the combination of the number of bronze ritual vessels (Ding and Gui) played a very important role in the status of a tomb owner (Table 1) [3,72]. However, it is important to note that there is a chronological lag between these historical sources and the Shang period and that these works might be biased by the views of the writers. Thus, caution and some skepticism are advised in the use of these textual sources, and they should not be viewed as undisputed fact.

**Table 1.** Summary of selected di fferences based on social class in ancient China. This information is referenced from LiJi " 礼 记" [5] except for "co ffin number" which was referenced from Xun Zi "荀 子" [6]. Note: Readers are advised that care must be taken with the accuracy of this information as it is compiled from historical sources which could be subject to the biases of the writers.


#### **3. Site of Xiaohucun, Henan Province, China**

The Xiaohucun site, dating to the late Shang (ca. 1250–1046 BC) and Western Zhou Dynasty (ca. 1046–771 BC), was the focus of a partial rescue excavation in 2006 by the Henan Provincial Institute of Cultural Relics and Archaeology. The site is situated to the northeast of Xiaohu Village in Xingyang City, which is about 20 km from Zhengzhou, the capital of Henan Province, China (Figure 2) [76]. This unique location is situated in the core of the Central Plains, which was the origin of many early civilizations of China, and also the political and economic center of the early Shang Dynasty. Based on archaeobotanical and isotopic research, the inhabitants of the Central Plains mainly relied on millet cultivation (rice and wheat were also present to some extent) and animal husbandry (pig, cattle, etc.) for subsistence [1,3,34,66,77–80].

**Figure 2.** Map of China showing the location of the (**a**) Xiaohucun site and (**b**) Guandimiao site. Note: Zhengzhou is the capital of Henan Province.

A total of 58 tombs from the late Shang Dynasty (ca. 1250–1046 BC) were excavated from an area of 400 × 200 meters. All tombs are pits and rectangular in shape, and most had a platform consisting of: inner coffin, outer coffin, waste pit, sacrificial dogs, and various types of grave goods. Unfortunately, many tombs have been looted and destroyed and only 21 of them could be studied in any detail. According to the preliminary report from this site, all the 21 tombs can be divided into three styles, equivalent to the phases of the Yin Ruins II, III, and IV [81]. No radiocarbon dates are available from the site, but examination of the tomb style, grave goods, and the writing on the bronze vessels sugges<sup>t</sup> that the cemetery was a family plot that belonged to the *She* "舌" family from the late Shang Dynasty. Many of the individuals were from the junior nobility class, but a number of common people were also interred here.

#### **4. Materials and Methods**

For the 21 tombs at Xiaohucun, bone samples consisting of long bone fragments were obtained from 12 late Shang Dynasty individuals for stable isotope ratio analysis. Osteological analysis, including sex determination and age estimation, was carried out according to standard methods [82]. Unfortunately, due to poor preservation and looting many of the skeletons were destroyed or incomplete and only 5 out of 12 individuals could be positively identified to gender and 9 out of 12 aged (Table 2). In addition, since Xiaohucun was a cemetery site, faunal samples were not available for study. However, we were able to obtain animal bones (n = 11) from the nearby (15 km) and contemporaneous site of Guandimiao (ca. 1250–771 BC) which serves as a baseline estimation for the human diets (Table 3).

Collagen was extracted at the Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China, using the protocol outlined by Richards and Hedges [83]. The extracted collagen was well preserved and the majority of samples had collagen yields of over 1% and C: N between 3.0–3.2 (11/11 animals; 12/12 humans), which is indicative of collagen suitable for isotopic analysis [84]. The samples were measured with an Isoprime 100 IRMS coupled with Elementar Vario. Standard material for testing the carbon and nitrogen content was sulfonamides. For every 10 samples, we interpolated one IEAE-CH-6, IEAE-N-2, and IEAE-600 to make data corrections. The measurement precision for δ13C and δ15N results is ±0.2%. SPSS 20.0 and Origin 8.0 were used for statistical analysis.


**Table 2.** Isotopic results and sample information for all humans from the Xiaohucun site, Henan Province, China.

**Table 3.** Isotopic results and sample information for all fauna from the Guandimiao site, Henan Province, China.

