Urkunden aus französischen und österreichischen Klosterarchiven: Besiegelungspraktiken und visuelle Muster
Creators: name: Laroche, Johannes
name: Tscherne, Niklas
Publisher: name: Zenodo
Year: 2024

description: Niklas Tscherne: The BeCoRe project is concerned with the use of visual features in large corpora of charters, specifically their connection with authority and validity, and what they may show us about the development of diplomatic traditions. One particular Computer Vision approach which we employ in this context is visual clustering, the basics of which will be introduced here.

The workflow utilised here consists of four steps: Preprocessing, feature extraction, dimensionality reduction, and the clustering itself.

Preprocessing is particularly necessary for us due to the visually heterogeneous nature of our images, which are taken from different sources and can be of dramatically different quality. Cropping and image binarization (in the sense of setting all pixels to be either white or black) help to somewhat diminish this heterogeneity, which could otherwise overshadow more subtle differences.

Feature extraction is the process of discovering and making quantifiable the most important features of an image. Two possible methods for this are Convolutional Neural Networks (CNNs) and HOG (Histogram of Oriented Gradients). Every feature extraction method is a particular way of “seeing” the data, which has a strong influence on the outcome. Different tasks can require different extraction methods.

Dimensionality Reduction is used to make the high-dimensional results of feature extraction easier to handle, compute, and visualise. One algorithm employed for this, UMAP, projects the data into two-dimensional space and attempts to preserve underlying structural relationships in the data.

Finally, assigning clusters to the data can also be achieved in a variety of ways, the choice of algorithm being influenced by the particular use case. Crucially, plots become meaningful through an understanding of the various features and parameters involved in their creation and an approach that values consistency over the cherry-picking of expected and desired results.

 

Johannes Laroche: I will delve into a traditional diplomatic inquiry concerning the influence of institutions or regions on the layout of late mediaeval charters. Drawing from an extensive analysis of charters issued by the monasteries of Göttweig, Lilienfeld, and Lambach—with particular attention to the latter's voluminous charter collection — I will scrutinise sealing practices to illuminate the diverse approaches observed in these monasteries.

While the sealing customs of the abbots and convent of Göttweig adhere to conventional norms, with both abbot and convent typically issuing and sealing charters jointly with their respective seals, the Cistercians of Lilienfeld demonstrate a distinctive practice shaped by the regulations of their order. Notably, the convent seal only became customary after 1335, following a reform bull of Pope Benedict XII.

The case of Lambach presents a more intricate scenario, evolving through distinct phases. Initially, until the late 14th century, the abbot and convent issued and sealed their charters together and used a common seal. Subsequently, from approximately 1380 to 1430, the convent gradually reduced its involvement in issuing and sealing charters jointly with the abbot, eventually ceasing altogether in the 15th century, except for charters concerning religious affairs such as confraternity charters. This apparent departure from the reform ideals of Melk, in which the abbot of Lambach played a prominent role, may be attributed to the growing complexity of managing the monastery's estates, necessitating specialised skills beyond the capabilities of the convent.

This observation directs attention to the lay officers of the monastery, particularly in the monastery’s chancery where the majority of deeds were likely drafted, as indicated by paleographical analysis. It underscores the pivotal role of the scribe in shaping the layout of these documents when it comes to the charter production of smaller late-mediaeval chanceries. At this documentary level, clustering methods may therefore regroup charters written by the same scriber, the issuers and sealers having less influence on their design. (Updated version: Signatures added)