Horse Skulls From Constantinople (Istanbul, Türkiye), 4th–15th Centuries ad: A Morphometric Analysis

Abstract

Horse skulls recovered from the Yenikapı Metro and Marmaray excavations in Istanbul, representing the Early to Late Byzantine periods, were investigated to assess cranial size, proportions, and morphological variability. A total of 503 horse skulls were examined, and 48 craniometric measurements and 11 cranial indices and ratios were recorded or calculated. To reduce size-related effects, the measurements were log₁₀-transformed prior to statistical analysis. Principal component analysis (PCA) showed that PC1 accounted for 41.5% of the total variance and represented overall cranial size, whereas PC2 explained 15.1% and primarily reflected regional shape variation in the palatal and dental regions. Together, PC1 and PC2 accounted for 56.6% of the total variance. The neurocranium and overall cranial proportions were relatively stable, whereas the viscerocranial and dental regions showed greater variability. Stepwise multiple regression analyses further demonstrated strong relationships between palatal dimensions and the longitudinal dimensions of the skull. Median palatal length was the strongest predictor of total length and basal length, with the final models explaining 75.6% and 86.2% of the variance, respectively. In contrast, the relationships between palatal and diastema measurements and transverse cranial dimensions were weaker, explaining 15.2% of the variance in greatest neurocranium breadth and 23.2% in greatest breadth of skull. The cranial indices, together with the Franck and palatal indices, supported a typical caballine morphology, whereas the observed variation indicates a heterogeneous population composed of different functional horse types rather than a standardized modern breed. The marked variability in the palatal and dental regions may reflect functional requirements, patterns of use, and selective breeding practices. These findings contribute to a better understanding of cranial morphological diversity, horse management, and breeding practices in the Byzantine period.