 During the fierce Investiture Controversy, Bertha's husband was excommunicated by Pope Gregory VII at the Lenten synod in Rome in 1076.In October, the German princes took the occasion and swore an oath at Trebur that they would no longer recognise Henry as king unless this excommunication was lifted.Henry thus had to cross the Alps and travel to Italy in order to meet with Gregory during the winter of 1076/77.