Although Celtis rejected the use of such fi gurative let-ters and he promoted his own alphabetic-associative system instead, still, Cusanus copied both methods in his treatise. However, he only copies the words of the mne-monic alphabet of Celtis but not the associative method itself. The fi rst fi ve elements of Celtis (in the work of Cusanus: abbas, eques, illuminator, organista, usurarius) are not associative topoi anymore, but only the scheme of a ready-made mental book (liber mentalis).