After Henry IV's excommunication in 1076, Herman released the prisoners he had been holding. In 1078, he went to the royal court with a large party of fellow Lotharingians to persuade Henry to yield. This only provoked the royal wrath and, in late April 1078, Hermann was forced into exile while a royal army occupied Metz in May. He spent the next few years in Liège, Verdun and Rome. Gregory VII named him an
apostolic legate. He supported
Hermann of Salm as king in opposition to Henry IV and represented him at Gregory's
Lenten synod of 11 February 1079. The date of his return to Metz is uncertain, but it was not before 1081. On 15 March that year, Gregory wrote to him to justify his second excommunication of Henry IV in 1080. This is "the longest and most widely noted of all Greogry's letters." In 1084, the emperor came to Metz in person to force Herman into exile. The
Council of Mainz in 1085 declared him deposed on the grounds that he had failed to attend. The emperor installed a rival bishop,
Walo, later replaced by . Hermann passed his exiled in Liège and Sint-Truiden. He also visited the Countess Matilda in Tuscany. In 1088, the townspeople forced Bruno out and invited Hermann back. ==Reconciled bishop==