Mandatory registration as a reader of the General State Archives and State Archives in the Provinces.
An important figure in CegeSoma and present since its launch in 1969, Frans Selleslagh wrote a thesis on activism between 1914 and 1916. For many years, he devoted himself to collecting and filing documents relating to the second war period. His main research interests were Christian Youth Workers, compulsory work in Germany, and the Catholic Church. He also contributed greatly to the development of the Centre’s Images and Sounds section by developing an awareness of the importance of these formerly overlooked sources. He left CegeSoma in 2002 to retire. He then volunteered to contribute to the classification of the archives of the Archdiocese of Mechelen. In October 2008, he died of illness.