Informal cooperation has existed for decades. It began under Director Erwin Gatz. The contact between the RIGG and the research centre of the Commission for Contemporary History in Bonn, whose director from 1993-2015 was Prof. Dr Karl-Joseph Hummel, is particularly close. Together with him, the RIGG organised the conference on the 100th anniversary of the death of the rector of the Campo Santo Teutonico, Anton de Waal, the proceedings of which were published in a comprehensive volume Papality and Patriotism. The Campo Santo Teutonico: Place of the Germans between the Risorgimento and the First World War.