He was acclaimed King of Germany in Verona in June 983, at the age of three, and crowned in Aachen on December 25 the same year. His father had died four days before the ceremony, but the news did not reach Germany until after the coronation.
In early 984 Henry the Quarrelsome, who had been deposed as Duke of Bavaria by Otto II, seized Otto and claimed the regency as a member of the reigning house. To further his object he made an alliance with Lothair of France. Willigis, Archbishop of Mainz, the leader of Otto's party, induced Henry to release the imprisoned king, for which his Duchy of Bavaria was restored. Otto was thus returned to his mother, the Byzantine Greek princess Theophanu, who served as regent thenceforth. She abandoned her husband's imperialistic policy and devoted herself entirely to furthering an alliance between Church and Empire. She was unable, however, to prevent France from speedily freeing herself from German influence. The regent endeavoured to watch over the national questions of the Empire in the East. One of the greatest achievements of this empress was her success in maintaining feudal supremacy over Bohemia.
After Theophanu's death in 991, Otto's grandmother, Adelaide of Italy, then served as regent together with Willigis until Otto III reached his majority in 994.
Otto's mental gifts were considerable, and were carefully cultivated by Bernward, afterwards bishop of Hildesheim, and by Gerbert of Aurillac, archbishop of Reims, so that he was called "the wonder of the world."
However, as soon as Otto had left Rome one year later, the city magnate Crescentius II deposed Gregory and installed John XVI as pope. Leaving his aunt, Matilda of Quedlinburg, as regent in Germany, Otto returned to Italy and retook the city in February 998, storming Castel Sant'Angelo. Crescentius was executed in the Castel Sant'Angelo, the antipope mutilated and blinded, and Gregory reinstated.
Otto made Rome the administrative center of his empire and revived elaborate Roman customs and Byzantine court ceremonies. He took the titles "the servant of Jesus Christ," "the servant of the apostles", "consul of the Roman senate and people" and "emperor of the world". When Gregory V mysteriously died in 999, Otto arranged for Gerbert to be elected pope as Sylvester II. The use of this papal name was not casual: it recalled the first pope of this name, who had allegedly created the "Christian empire" together with Constantine the Great. Otto therefore was to be seen as the ideal successor to Constantine in the task of reunifying the Roman Empire.
Between 998 and 1000 Otto, being a fervent Christian, made several pilgrimages. He travelled to the Gargano Peninsula in Southern Italy and to Gaeta, where he met Saint Nilus the Younger, then a highly venerated religious figure. Later he left Italy, taking the pro-Byzantine Duke of Naples, John IV, captive with him, for the tomb of Adalbert of Prague (who in the meantime had been martyred by the pagan Prussians) at Gniezno, and during the meeting with Bolesław I the Brave in the Congress of Gniezno he founded the archbishopric of Poland. In Eastern Europe Otto and his entourage strengthened relationships with the Polish Duchy and with Stephen of Hungary, who had requested and been granted a crown by Sylvester. Otto was advised by St Romuald, the fervent reforming hermit idealized by Peter Damian in the "Vita beati Romualdi". Romuald urged Otto to become a monk.
Another model to which Otto strongly aspired was Charlemagne. In the year 1000 he visited Charlemagne's tomb in Aachen, removing relics from it. He had also carried back parts of the body of Adalbert, which he placed in a splendid new church he had built in the Isola Tiberina in Rome, now San Bartolomeo all'Isola. Otto also added the skin of Saint Bartholomew to the relics housed there.
A minor rebellion by the town of Tibur (Tivoli) in 1001 ended up as his undoing. He retook the town, but spared the inhabitants, which angered the people of Rome, as Tibur was a rival they wanted destroyed. This led to a rebellion by the Roman people, headed by Gregory, Count of Tusculum; Otto was besieged in his palace and then driven from the city. He withdrew to Ravenna to do penance in the monastery of Sant'Apollinare in Classe. After having summoned his army, Otto headed southwards to reconquer Rome, but died in the castle of Paterno, near Civita Castellana, on January 24, 1002. A Byzantine princess had just disembarked in Puglia, on her way to marry him.
Henry succeeded him as king of Germany (and later as emperor) as Henry II.
Rethinking Otto III-Or Not: Chris Wickham Revisits an Article by J.B. Morrall, First Published in History Today in 1959, on the Strange, Shortlived Emperor Who in the Tenth Century Sought to Rule the Lands We Now Call Germany and Italy
Feb 01, 2011; J.B. Morrall in 1959 wrote what was for the period a pretty good account of Otto III's unusual but brief career. Why Morrall, who...