After Otto I ascended the throne in 936, he actively attacked feudal separatist forces, resisted magyars's invasion and maintained centralization.
After the rebellion of the Duke of Bavaria was put down in 937, the hereditary system of the Duke was changed to the appointment system of the king, and the Duke was deprived of his religious rights. By means of conquest and marriage, by 949, he completely controlled the five principalities of Schwaben, Fran Kenya, Lorraine, Bavaria and Saxony, and established a powerful kingship. He used Christianity to colonize east of the Elbe River and killed Slavs in the west.
In 95 1 year, he invaded Italy, married the widow of the Italian king, and was crowned king of Italy (or Lombardy) in pavia.
In the Battle of augsburg in 955, the Hungarian invasion was completely shattered.
In 19961year, at the request of Pope John XII, he once again marched into Italy to quell the local rebellion.
In February of the following year, he was crowned Emperor of the Roman Empire in Rome.
In 963, Otto deposed John XII and made Leo VIII Pope. This also set a precedent for the emperor to decide the pope and became the prelude to the long-term struggle between the emperor and the pope in history.
In 966, he sent troops to South Italy, but was resisted by the Byzantine Empire and forced to make peace.
His long-term foreign expansion policy not only brought suffering to the people in the invaded areas, but also affected the reunification of Germany.
During the reign of Otto I, with the help of religious forces, the rule was strengthened and expanded, which once brought suffering to the people in the invaded areas. The title of "Roman Empire" he created was passed on to the next generation. In 1 157, Frederick I (red beard), the first king of Hohenstaufen dynasty, added the word "sacred" before "Roman Empire" to show his national prestige and martial arts achievements, thus becoming a holy Roman Empire, and the power and territory of the empire reached its peak.
Otto's most influential measure in internal affairs was to declare the diocese a fief, and bishops enjoyed all the secular rights of lords, which made bishops a solid pillar for supporting Otto's huge empire. During the eastward expansion of the empire, the activities of the church in ideology also made great contributions. In order to maintain the long-term rule of the newly conquered Slavs, Otto established new dioceses in these areas, such as magdeburg Archdiocese, quedlinburg, Mesburg and Meissen, which was of great significance in the process of the Christianization of Slavs.
Italy is located at the crossroads of East-West trade. Its cities such as Venice, Genoa, Milan and Florence are rich places in Europe, and German feudal lords have long coveted them. The chaos of Italian political situation gave the invaders an opportunity: the northern governors such as Afria and Spoleto competed for the throne, while the southern part was the sphere of influence of Byzantium and Arabs. The Pope is very corrupt. Theo Fejlek, a Roman aristocrat, and his wife and daughter manipulated the abolition of the Pope for half a century, which caused widespread dissatisfaction from all walks of life. In 955, Pope John XII (955-964) ascended the throne. He lived a dissolute life, squandered money and committed crimes openly. Some Vatican officials are determined to get rid of him and hand over power to the king of Saxony. They sent a special envoy to meet Otto and invited him to Italy and Rome. In 19961year, Otto led a large number of troops into Italy and was crowned Augustus in St. Peter's Cathedral in Rome in February the following year. In this way, nearly 500 years after the demise of the Western Roman Empire, a "Roman Empire" appeared, and later it was even called the "Holy Roman Empire", meaning that it had the right to rule all Christian kingdoms and was the true successor of the Roman Empire who believed in Christianity. From then on, every German king wanted to repeat the coronation ceremony to Rome after taking office, which was a great honor.
In the last ten years of Otto's reign, he concentrated on attacking Italy, manipulated and abolished the Pope many times in an attempt to guide Italy, thus colliding with Byzantine and Arab forces entrenched there. In 970, Otto made peace with Byzantium, and was forced to give up his ambition for South Italy, and married his son, later Otto II, to Theofino, the daughter of Romenus II, the first emperor of Byzantium. Otto II (reigned from 973 to 983) inherited his father's legacy, and once occupied Nablus and taranto, but was defeated by Arabs in 982. In 983, he presupposed a 3-year-old prince (regent by his grandmother and mother), determined to cross the rubicon and March into Italy, but failed. I died in Rome. Otto III (in office from 983 to 1002) made several expeditions to Italy, and I also died in Rome. When his body was transported to the north of Verona, it was attacked by local residents.
The conquest of Italy by Otto I and his successors not only brought pain and disaster to the Italian people, but also brought misfortune to the German nation. They spend all their effective strength on the war, and they tend to lose sight of one thing and be exhausted. In this way, the cause of national reunification, which was already in sight, finally came to nothing. Engels said: "Although there is a lack of economic ties within Germany, it was originally centralized, even earlier (for example, during the Otto dynasty)." However, "the title of Roman emperor and the resulting ambition to dominate Europe made it impossible to form a nation-state and exhausted its strength in all previous battles to conquer Italy."