This is the latest version of my Master's thesis that I handed in on the 4th of September 2023 and defended successfully on the 2nd of November 2023. A huge thank you goes to Dr. Mareike König (German Historical Institute in Paris) and Prof. Dr. Christof Schöch (University of Trier) who supported and motivated me throughout this last step of my Master's degree in Digital Humanities.Abstract: The significance of research data is steadily increasing. Their analysis and re-use enable new scientific insights. Alongside large-scale digitisation projects and the interest in big data, small and medium-sized research institutions have also launched digitisation and indexing projects. Just a few years ago, there were no standards for such projects. Data were often created in accordance with specific research questions and the wishes of researchers – and are therefore not available in a standardised form. Today, the necessary standards are being established by research data infrastructure initiatives such as NFDI. Questions such as "How can data – regardless of size – be standardised and thus saved from ending up in the data graveyard?", "How can data be made accessible and opened up for new research questions?" are becoming common in the research community and affect researchers regardless of their discipline. This thesis aims to explore the potential of transforming an existing data basis into a standardised linked open data model using the Semantic Web, ontologies and knowledge graphs. In addition, a new exploratory search option for the correspondence in the form of an interactive knowledge graph visualisation intends to enable renewed access to the data. Drawing on the limitations of the resulting user interface and visualisation, the project also outlines potential future research and improvements.