The MeMO database is the result of a catalogue project. The information provided is based partly on extensive research over the past two decades, especially where the memorial images are concerned (Van Bueren). The results of this research were used for the database and website Representations of Medieval Memoria (Memoria in Beeld), a direct precursor of the MeMO database. The data in Representations of Medieval Memoria have now been included in the present database, in which descriptions have also been included of newly discovered memorial images. The research into the memorial images studied the actual images or used photographs.

A large number of the floor slabs and tomb monuments have been researched in situ and have been photographed by a professional photographer (subsidised by the Cultural Heritage Agency (RCE). We have moreover made use of the photographic collections and information of various parties, including the Foundation for Ecclesiastical Art and Artefacts Netherlands (SKKN), a number of churches, Van Hoogevest Architecten and private persons, for which we are grateful. In part MeMO had to rely on (older) literature, because it was impossible for us to visit every holding institution to perform on-site research. Moreover, a number of objects could not be traced due to (recent) restorations and refurbishments and relocations.

The descriptions of the memorial registers are partly based on research of the text carriers themselves, but also on digitised images of the manuscripts and additional information provided by the holding institutions. A large part of the inventory is based on the inventory project of the nineteen nineties by members of Contactgroep Signum. This project was continued in the period 2004-2006 by Werkgroep Memorieboeken that also initiated a pilot for the description of memorial registers.

For the narrative sources MeMO made use of the Narrative Sources project, which is based in turn on the inventory of Carasso-Kok. Not all narrative sources could be consulted within the framework of the MeMO project, which is why it is possible that not all required information has been included in MeMO. This has been indicated in the descriptions in the relevant cases.

See the chapters 3 (objects), 4 (text carriers and texts) and 5 (institutions) for an overview of the sources and research on which the information is based.