It is with great sadness that we report that one of the ESWC founders, Dieter Fensel, passed away in Innsbruck on December 29th, 2024 after a long illness. Dieter was born in Nuremberg, Germany, on October 10th, 1960. His early education was conducted in and around Nuremberg after which he went on to study mathematics at the Free University of Berlin where he earned a Master’s degree in Social Science. He also earned a Master’s degree in Computer Science from the Technical University of Berlin.

Following this Dieter enrolled at the University of Karlsruhe, where he obtained his doctorate in 1993 under the supervision of Rudi Studer. He later completed his habilitation at the same university and was honored with the Carl Adam Petri Award for his work. In 1994 Dieter moved to the University of Amsterdam after gaining a two year scholarship from the German Research Foundation. Following this, he took on the role of associate professor at the Vrije Universiteit Amsterdam. The 2000s saw the Semantic Web emerge as a new and vibrant research field and in 2002, Dieter became a full professor at the University of Innsbruck and in 2003 at National University of Ireland, Galway as well. It was at this time that he founded the Digital Enterprise Research Institute (DERI) at both of his new affiliations in Innsbruck and Galway. The Innsbruck institute was later renamed into the Semantic Technology Institute (STI) Innsbruck, where Dieter remained serving as the Chair until his passing.

Whilst the above captures the main essentials of Dieter’s career it is not easy to put into words his contributions to ESWC and the Semantic Web movement in general. Dieter was a true visionary and he saw at the very beginnings of the Semantic Web movement that a comprehensive and broad international research infrastructure would be required for the field to truly take off and have lasting impact. It was he that advocated for the setting up of the main conferences, ISWC as well as ESWC, and also that a high quality journal to capture research outputs was required as well as a summer school to train and inculcate the next generation.

As stated on the ESWC history page, this conference series started over 20 years ago as the European Semantic Web Symposium held in Heraklion, Greece in May of 2004. This first event was established and supported through three large European projects that Dieter had a leading role in (SEKT, DIP and Knowledge Web). Since that time, as ESWC grew, and was relocated to Budva in Montenegro, Innsbruck, Tenerife, Montpellier and Portoroz (more than once), before coming back to Heraklion, Dieter was the main driver behind the scenes ensuring that the conference has had sustained success over a two decade period.

Over that time, he never lost his passion for all things related to semantics and his vision that semantics takes its rightful place at the centre of computer science impacting society globally. This insight, as AI establishes itself at the top of the news agenda, remains as true today as it was back in the last century.

As all who worked with him quickly found out Dieter was a unique individual. He valued honesty, authenticity, clarity and excellence, whilst advocating that the main barriers in work (and life) were self-imposed. He also believed that culture and environment were fundamental aspects of fulfilling work and expended substantial energy engineering the highest quality of both within his research institutes and for colleagues and participants at any event or meeting he organised. Dieter was a very rare individual able to provide visionary and strategic leadership whilst also ensuring that the well-being of staff, colleagues and event participants was comprehensively covered.

We remain hugely grateful for all of Dieter’s contributions over the last two decades, especially for establishing this conference series. We will all miss him greatly.

May he rest in peace.

January 2025