This publication presents the abstracts of What’s Past is Prologue: The NewsEye International Conference organised by the consortium of the EU Horizon 2020 research and innovation programme project NewsEye: A Digital Investigator for Historical Newspapers. This conference, which was held online on the 16th and 17th of March 2021, featured four keynote speakers and over thirty presenters hailing from eleven countries. Spanning from May 2018 to January 2022, NewsEye is a research project advancing the state of the art and introducing new concepts, methods and tools for digital humanities by providing enhanced access to historical newspapers for a wide range of users. Hence, the conference theme Towards a future of interdisciplinary collaboration between Cultural Heritage, Digital Humanities, Computer Science and Data Science reflects certain aspects of the NewsEye project itself. The NewsEye consortium is composed of three national libraries and eight research groups based in Austria, Finland, France and Germany, which have each contributed specialised knowledge in the aforementioned subjects.