In order to compare the early life experiences of different population subgroups from the Early Medieval centre of Mikulčice, carbon and nitrogen isotopic values were measured in dentine serial sections from the rst permanent molar of 78 individuals. Age-at-death, sex (estimated in subadults with the help of proteomics) and socio-economic status were considered as explicative variables. Average values of both nitrogen and carbon maximal isotopic offset within the isotopic pro le were higher than the recommended range for weaning under healthy circumstances: 3.1 ± 0.8‰ for Δ 15 N max and 1.6 ± 0.8‰ for Δ 13 C max . Individuals who died during the rst decade of life showed earlier ages at the nal smoothing of the nitrogen isotopic curve (suggesting complete weaning) than older individuals. Most individuals (n = 43) showed positive covariance between δ 15 N and δ 13 C values during the period of breastfeeding. The average δ 15 N values from the post-weaning period were similar to those of bone, while post-weaning δ 13 C values were signi cantly higher.Though an increased Δ 15 N max suggests a common presence of physiological stress, the intra-population comparison of early life experiences does not suggest that individuals who died during their rst decade experienced greater levels of environmental stress during infancy.The predominance of positive covariance between carbon and nitrogen isotopic values during the breastfeeding period, together with an increased Δ 13 C max and increased post-weaning δ 13 C, suggest that millet was either a part of a special diet preferred during lactation or was introduced as a rst dietary supplement.