AbstractNoble and commoner in the medieval China capital of Chang’an (modern-day Xi’an) engaged in an intricately intertwined agricultural and pastoral economy. The period represents the peak of the integration of nomadic and agricultural populations in early China. Here we firstly reported human collagen δ¹³C and δ¹⁵N values for eight middle age nobles whose lifespans cover roughly a century (AD 503–604) and who include a Northern Zhou, Emperor Wu (北周武帝) and his consort, Empress A’shina (阿史那皇后). We also consider stable isotopic evidence from nine individuals in commoner burials in the Chang’an region, likewise dating to the sixth century. This century-long dietary profile provides direct archeological evidence for dietary variability at this core metropolitan population. Constructing a comparative model using existing historical human isotopic data (n = 1233) from northern China and its northern Steppe, we find a marked regional divergence in noble and commoner dietary patterns. We trace this back to the considerable variety of agricultural and pastoral dietary practices, likely pointing to different economic and geographic backgrounds of the individuals under study. We argue that a two-way relationship between shifting pastoral and agricultural practices was reflected to separate degrees at the elite and commoner level. This study offers an improved understanding of the multiplicity of dietary patterns and associated lifeways for the metropolitan societies of medieval northern China.