Breastfeeding, and weaning practices in the Goryeo cemetery (1170–1392 CE) at Geumseong-ri, Jeju, South Korea: A Bayesian model approach

초록

Reconstructing breastfeeding and weaning practices in past societies have provided valuable information about health and nutrition of infants and children. In 2012–2013 archaeological fieldworks, exceptionally well-preserved juvenile skeletons were excavated from a Goryeo cemetery at Geumseong-ri, Jeju Island, South Korea. In this study, we analyzed stable carbon and nitrogen isotopes of well-preserved juvenile (n = 39), and adult (n = 15) remains from the Geumseong-ri cemetery to reconstruct breastfeeding and weaning practices in the medieval Jeju population. We applied the Bayesian WARN (Weaning Age Reconstruction with Nitrogen Isotope Analysis) model to evaluate the period of breastfeeding and weaning practices and used the Bayesian mixing model (MixSIAR) to estimate dietary sources during the weaning period. The WARN model shows that the start of weaning occurred close to 0.4 years of age and the end of weaning in the Jeju population was 2.1 years. The MixSIAR model outputs reveal that most Geumseong-ri infants were weaned using C3 plants (barley, buckwheat and rice). Despite its proximity to coastal environments, the weaning sources of children at the Geumseong-ri primarily comprised of C3 plants and terrestrial animals. Our study reveals that both the initiation and termination of weaning in infants during the Goryeo period occurred earlier than those observed in earlier periods, with C3 plants serving as the primary weaning foods for the medieval Jeju populations. © 2026 Elsevier Ltd