Columbia subject headings:
Germany--History--Hohenstaufen, 1138-1254--Sources.
Wibald, Abbot of Corvey, 1098-1158--Correspondence.
Harvard subject headings:
Germany--History--Hohenstaufen, 1138-1254--Sources.
Wibald, Abbot of Corvey, 1098-1158--Correspondence.
Princeton subject headings:
Abbots--Belgium--Correspondence.
Germany--History--Hohenstaufen, 1138-1254--Sources.
Letter writing--History.
Wibald, Abbot of Corvey, 1098-1158--Correspondence.