Modeling the Invisible: Applying the Unseen Species Model to Chivalric Literature in the Iberian Peninsula

This study applies an unseen species model—a non-parametric estimator originally developed in ecology—to the problem of textual loss in medieval Iberian chivalric literature. Drawing on abondance data for Castilian, Portuguese, and Catalan works, it estimates the number of lost or unrecorded texts based on the frequency of rare items. The results suggest that only about 40 % of the original corpus and roughly 8 % of individual documents have survived, indicating that the extant record represents only a small fraction of the field’s former scale. Beyond numerical estimation, the approach demonstrates how probabilistic modelling can inform literary historiography, providing a structured framework for reasoning about absence and survival.