Intrapopulation Variation in St. Peter’s Medieval (Tenth-Sixteenth Centuries) Cemetery (Osor, Croatia)

This study investigates intrapopulation variation within the medieval cemetery from Osor, Croatia (900–1500s A.D.), by examining diet, nonspecific stress, and mortality risk using multivariable statistical methods. The δ13C and δ15N stable isotope analysis, macroscopic analysis of osteoblastic nonspecific lesions, and age-at-death data were collected for 196 monastic and lay individuals from five burial sectors in St. Peter’s Monastery cemetery. Binary and multinomial multiple logistic regression were employed to analyze intrapopulation variation. The multivariable analyses reveal that dietary stable isotope values, prevalence and characteristics of nonspecific lesions, and age at death varied significantly between Osor’s lay and monastic samples, as well as between the various lay burial sectors. Notably, Osor’s monastic population’s diet significantly differed from that of lay individuals, exhibiting lower δ15N and higher δ13C values. Additionally, monastic individuals showed a higher prevalence of nonspecific lesions, with more nonspecific lesions and larger nonspecific lesions than lay individuals. While the presence of nonspecific lesions was associated with older ages at death, monastic individuals did not exhibit lower levels of mortality risk. Osor’s elite individuals consumed a more protein-rich diet with more marine resources compared to Osor’s wider lay population and monastic individuals. These elite individuals displayed greater levels of frailty, evidenced by higher mortality risk and lower nonspecific lesion prevalence, however. Finally, lay individuals from burial sector 6 differed from the wider lay population and exhibited lower δ15N and δ13C values and higher average age at death, indicating a more terrestrial protein-based diet and lower mortality rates.