Medieval history, particularly diplomatics, have seen a peak in the publication of printed resources in the last decades of the 19th century. These resources are known to be the most extensive overview of the documents issued during the medieval period, and they contain short summaries of medieval charters, called regesta documenting all relevant legal acts. The research presented in this paper is based on a project that investigates the disputed election of Pope Alexander III and the resulting schism during his mandate from 1159 till 1177. Hence, a period that saw a culmination in issuing legal documents. The aim of the project can be divided into two tasks; the first task consists of an updated systematic overview of all textual witnesses from said period in a machine-accessible condition. The second aim is to use the encoded and annotated summaries (regesta) to re-assess the dynamics and processes that led to overcoming the schism between the opposing parties, namely the supporters of Pope Alexander III and those of the Holy Roman Emperor Frederick I Barbarossa. The presentation examines the development of a data model designed to enable a new, quantitative approach to analysing the information encoded in textual witnesses. The research presented in this paper is part of the project Forming Europe by Overcoming Schism in the Twelfth Century, funded by the Union of the German Academies of Sciences and Humanities since 2023, for further information see: https://formierung-europas.badw.de/.