Henry IVsonof Henry III
Henry IV. (son of Henry III.) was born in 1050, and was elected King of the Romans when a child. He was not crowned emperor till the year 1070; five years later at Hohenburg he avenged himself on the Saxon nobles for the humiliating terms he had been previously obliged to make with them, but his triumph was only for a time. In 1076 the great Investiture struggle began. Both Pope and emperor claimed a voice in the appointment of each other, and Gregory VII. declared it to be a sin for an ecclesiastic to accept any benefice under conditions made by a layman.
Henry proclaimed the deposition of Gregory, who, in his turn, excommunicated him and declared his subjects absolved from their allegiance. The uncrowned emperor, finding himself without support in Germany, came to Italy in 1077, and obtained absolution, after standing barefoot and clothed only in a hair shirt for three winter days and nights in the courtyard of Canossa. The contest, however, was soon renewed; and the excommunication of Henry was answered by the nomination of a new Pope, by whom, after Rome had been captured, Henry was at length crowned. Gregory took refuge at first in San Angelo, and afterwards with Robert Guiscard, and the emperor was. for the time, victorious. He now, however, had to deal with fresh trouble in Germany, caused by his turbulent nobility, and no sooner were they subdued than he appeared again in Italy to meet tiie Guelf nobles.
In spite of his efforts, even his natural son Conrad turned against him, and soon after his coronation as King of the Romans the heir to the Empire himself was induced by Pope Paschal II. to depose and imprison his father. The last days of the great Emperor were passed at Liege, whither he had escaped, and where he died in 1106. Henry V. (1106-25) continued the struggle, which was brought to a conclusion by the compromise of the Concordat of Worms (1122).