The year 2030 marks the 500th anniversary of the presentation of the Confessio Augustana (CA) to Emperor Charles V at the Imperial Diet of Augsburg. The CA is not only of outstanding importance in terms of history and imperial law. It also provides a model of mutual recognition that had not previously been recognised, in which a unity is conceived that does not relativise the differences. Such a model of 'provisional recognition', which Philipp Melanchthon had in mind at the time, is currently being discussed in new socio-philosophical drafts of the Frankfurt School. Critical theory is increasingly focussing on the phenomenon of how mutual recognition is possible when differences cannot be reconciled but remain. The lecture will bring the CA into dialogue with drafts by Axel Honneth, Rainer Forst, Thomas Bedorf and Rahel Jaeggi in order to open up new possibilities for mutual recognition in ecumenism.