Holy Roman EmperorHenry IVThe Pope and the Holy Roman Emperor had disputed over the precedenceof ecclesiasticalor secularpower since the spread of the Gregorian Reforms in the 11th century. When Gregory VII, acclaimed Pope by the people of Rome in 1073, attempted to enact reforms to the investitureprocess by his Dictatus papae decree, he was met by resistance from Henry IV. The king insisted that he reservethe traditionally established right of previous emperors to "invest" bishops, abbotsand other clergymen, despite the papaldecree.The conflict became increasingly severe, after Henry had been able to suppressthe Saxon Rebellionin the Battle of Langensalza in June 1075. In September he installed a new Bishop of Milan, which annoyed Gregory who openly required obedience. Shortly afterwards the Pope became the target of an assassination attempt during the 1075 Christmas celebrations. On 24 January 1076, Henry assembled several German bishops in a synodat Worms, where the ecclesiastical dignitariesabandoned all commitments to the Pope. The king finally demanded Gregory's abdication, referring to the rules of papal election according to the In nomine Domini bull of 1059.In response, Gregory excommunicatedand deposed Henry in the Lenten synod of 1076 at Rome. He stated furthermore that, one year from that day, the loss of kingshipwould become irrevocable.Gregory had also declared the oaths of allegiancesworn by the Princes null and void, which turned out to be more dangerous to Henry's rule, as the development met the interests of several territorial rulers in the Empire. When in October the Patriarchof Aquileia and the papal legatemet with German princes at Trebur, they swore an oath not to recognize Henry unless the ban was lifted within a year. Fearing further rebellion among the German aristocracy, Henry felt he had to get rid of his excommunication. He was still popular among the common people, but the princes were threatening to elect a new king. He had to secure his position in the church before the rapidly approaching deadline given by the pope.On the suggestion of his adversaries, he arranged to meet with the Pope who had set out along the path across the Alps towards Augsburg. Henry beganhis trip in Speyer and, travelling southward down the Rhine, he found his position dangerous. As the Swabian nobles refused to open the way to the Alpine passes, the king had to move through Burgundy and cross the Alps at steep Mont Cenis. Henry, his wife Bertha of Savoy, and their young son Conrad risked their lives in harsh mid-winter conditions. After a long journey, they reached Gregory's accommodation in Canossa on 25 January 1077.9.Which of the following word or phrase can replace the underlined word “irrevocable”in paragraph three？