I. S. Robinson, (Cambridge, 1999). T. J. H. McCarthy: (Manchester, 2014). Gerd Althoff (Ed.): (Ostfildern, 2009) (Vorträge und Forschungen; 69). Gerd Althoff: (Darmstadt, 2006) Charter given by Henry to the bishopric of Bamberg, 17.8.1057. Photography taken from the collections of the Lichtbildarchiv älterer Originalurkunden at Marburg University showing the emperor's seal.