The Glagolitic script, one of the oldest known Slavic scripts, presents a substantial challenge for historical manuscript decryption due to its intricate glyph forms and limited existing digital resources. This paper introduces a novel dataset of Glagolitic letters aimed at facilitating the application of machine learning algorithms in the decipherment of historical documents. The dataset creation process comprised several critical stages: collection of raw data, preparation of images, application of neural networks for letter extraction, clustering of images, training of models to discern noise, and manual validation and annotation of rare letters. The resultant dataset stands as the first publicly accessible Glagolitic script resource tailored for deep learning applications in historical document analysis.