On this day, 949 years ago, on January 24, 1076 (December 16, the 1075 lunar calendar), Roman Emperor Henry IV was expelled from the Catholic Church by the Pope, and a conflict between church and state broke out. On February 14, 1076, Holy Roman Emperor Heinrich IV was expelled from the Catholic Church by Pope Gregory VII, and a famous religious conflict broke out in European history. Henry IV (November 11, 1050-August 7, 1106) was the third German King (reigned from 1056 to 1105) and Holy Roman Emperor (crowned in 1084) of the Franconian Dynasty (also known as the Sarian Dynasty). His fierce struggle with Roman Catholic Pope Gregory VII has been a topic of interest to historians. After Henry IV became king, he devoted himself to strengthening the royal power. However, the German princes were powerful and unwilling to obey his orders, and the Roman Church enjoyed the privilege of not being governed by secular powers. Henry IV decided to confront both. In 1075, Henry IV's conflict with the Church became apparent. He insisted on controlling the appointment rights of all bishops in Germany and northern Italy, and refused to allow the Archbishop of Milan, who was supported by the Pope, to take office, which led to a fierce conflict with Pope Gregory VII. Gregory VII was determined to put the Pope's power above secular rulers. At the end of 1075, Gregory VII warned Henry IV not to interfere in the affairs of the Holy See or face excommunication. This led to an open conflict between the emperor and the pope in the form of a power dispute. In January 1076, Henry IV announced the abolition of Pope Gregory VII. In a letter to the Pope, Henry IV wrote: "I, Henry, in the name of the King and all the bishops, declare to you-step down! Step down! Destroy in the torrent of the times!" In retaliation, Gregory VII expelled Henry IV from the Catholic Church on February 14, 1076. According to Catholic Church regulations, if the punished person cannot obtain the Pope's pardon within one year, his subjects must take an oath of disloyalty to him. Most German princes stated that if Henry IV could not restore his religion within a year, they would no longer recognize his legitimacy. Henry IV did not have enough troops to subdue the rebellious princes, and he had to bow to Gregory VII. On January 25, 1077, Henry IV rushed to Canosa Castle, the residence of Gregory VII, and is said to have stood barefoot in the ice and snow outside the castle for three days; he begged Pope Gregory VII to forgive him for all his sins. Gregory VII, knowing that Henry IV could not keep his promise, finally cancelled the punishment of expelling Henry IV from the Holy See. The Canosa Incident brought the power of the Holy See to its peak. Since then, the "Journey to Canosa" has become synonymous with humiliation and surrender in the Western world. Henry IV did not swallow the humiliation he suffered. After the vassals had no excuse to oppose him, he quickly attacked the rebels, defeated the rebellious vassals, and captured the newly elected new king, Rudolf, Duke of Swabian. Henry IV ordered Rudolf's hand to be cut off. Realizing that the situation had changed, Gregory VII excommunicated Henry IV again in 1080, and Henry again announced the abolition of the Pope and appointed a new Pope, Clement III. In 1084 Henry IV led his army to capture Rome, where he received the coronation of Clement III. Gregory VII abandoned the city and fled to Salerno, where he appealed to the Sicilian Normans for help. The Normans did drive Henry IV out, but they also sacked Rome. Gregory VII died in exile in 1085. Life was also difficult for Henry IV, facing a series of troubles. The successor Pope colluded with other German princes, and in 1090 Henry IV attacked Italy again, but failed to win. In 1093, his eldest son Conrad launched a rebellion. In 1105, his youngest son Henry rebelled. The rebellion was a success and the new king, Henry V, came to power. Henry IV was imprisoned by his son Henry V, but later managed to escape and died shortly afterwards. The death of Henry IV did not mark the end of the political struggle between theocracy and secular regimes. The seeds of hatred planted during Canosa's trip have influenced subsequent generations of Holy Roman and Catholic emperors. In 1122, a century-old struggle for power exhausted both sides, so the "Worms Religious Agreement" was signed. The agreement stipulates that bishops in Germany are freely elected by clergy without interference from the emperor; Such elections must be effective under the supervision of the emperor. The authority of a bishop in the territory is granted by the emperor, with the symbol of authority, and the religious authority is granted by the Pope, with the ring as its symbol. From then on, the power struggle between the Holy Roman Emperor and the Holy Pope came to an end.