Henry IV appointed Guibert of Ravenna (whom he had invested as bishop of Ravenna) and called Clement III (known by the Catholic Church as antipapst Clemens III) « our Pope. » In 1081, Henry attacked Rome and besieged the city with the intention of abducting Gregarious VII and installing Clement III. The city of Rome resusted at the seat, but the Vatican and St. Peter fell in 1083. On the outskirts of the city, Henry won thirteen cardinals, who became faithful to his cause. The following year, the city of Rome and Henry triumphantly entered the city. On Palm Sunday 1084, Henry IV De Clemens was solemnly inducted into St. Peter`s Basilica; On Easter Day, Clement returned his favors and crowned Henry IV as emperor of the Holy Roman Empire. The situation worsened when Henry IV appointed his chaplain Tedald, a Milanese priest, as bishop of Milan, while another priest from Milan, Atto, had already been elected in Rome by the Pope to be a candidate.  In 1076, Gregory responded by excommunicating Henry and denying him as king of Germany and freeing all Christians from their oath of allegiance.  The Investiture Controversy, also known as the investiture contest, was a conflict between church and state in medieval Europe over the ability to choose and install bishops (investiture) and abbots of monasteries and the pope himself. A series of popes in the 11th and 12th centuries interrupted the power of the Holy Roman Emperor and other European monarchies, and controversy led to nearly 50 years of civil war in Germany. The concordate of Worms (Latin: Concordatum Wormatiense)  is sometimes called Pactum Callixtinum by papal historians, since the term « Concordkordat » was not used until 1434 by Nicolas de Cusas De concordantia catholica.
[a] The prohibition of the secular investiture in Dictatus papae did not shake the loyalty of William`s bishops and abbots. During the reign of Henry I, the heat of the exchanges between Westminster and Rome caused Anselm, Archbishop of Canterbury, to renounce and retire to an abbey. Robert von Meulan, one of Henry`s senior advisers, was excommunicated, but the threat to excommunicate the king was not played out. The papacy needed the support of the Englishman Henry, while the German Heinrich was still uninterrupted. A planned crusade also required English support. Doctrine was of the utmost importance in the relationship between the Church and the temporal state, in matters such as ecclesiastical privileges, the actions of monarchs and even successions. The creation of the term « papal supremacy » dates back to the 6th century, at the time of the fall of the Western Roman Empire, which was the beginning of the rise of the bishops of Rome, not only the position of religious authority, but the power to be the ultimate master of the kingdoms within the Christian community that it retained since then. A concordant is an agreement between the Holy See and a sovereign state that defines the relationship between the Catholic Church and the State in matters that concern both i.e. the recognition and privileges of the Catholic Church in a given country and with secular issues that affect the interests of the Church. After the decline of the Roman Empire and before the inauguration controversies, the investiture, although theoretically a task of the Church, was carried out in practice by members of the religious nobility.
Many bishops and abbots were themselves part of the reigning nobility. As an older son would inherit the title of father, siblings often found a career in the church.