In the year 799, Pope Leo III. suddenly appeared in Charlemagne's camp at Paderborn, a fugitive from a conspiracy of the Roman nobles, by which his life was threatened. He was received with all possible honors, and after some time spent in secret councils, was sent back to Rome with a strong escort. In the autumn of the following year, Charlemagne followed him. A civil and ecclesiastical assembly was held at Rome, and pronounced the Pope free from the charges made against him; then (no doubt according to previous agreement) on Christmas-Day, 800, Leo III. crowned Charlemagne as Roman Emperor, in the Cathedral of St. Peter's. The people greeted him with cries of "Life and victory to Carolo Augusto, crowned by God, the great, the peace-bringing Emperor of the Romans!" If, by this step, the Pope seemed to forget the aspirations of the Church for temporal power, on the other hand he rendered himself forever independent of his nominal subjection to the Byzantine Emperors. For Charlemagne, the new dignity gave his rule its full and final authority. The people, in whose traditions the grandeur of the old Roman Empire were still kept alive, now beheld it renewed in their ruler and themselves. Charlemagne stood at the head of an Empire which was to include all Christendom, and to imitate, in its civil organization, the spiritual rule of the Church. On the one side were kingdoms, duchies, countships and the communities of the people, all subject to him; on the other side, bishoprics, monasteries and their dependencies, churches and individual souls, subject to the Pope. The latter acknowledged the Emperor as his temporal sovereign: the Emperor acknowledged the Pope as his spiritual sovereign. The idea was grand, and at that time did not seem impossible to fulfil; but the further course of history shows how hostile the two principles may become, when they both grasp at the same power. [Sidenote: 800. CHARLEMAGNE'S EMPIRE.] The Greek Emperors at Constantinople were not strong enough to protest against this bestowal of a dignity which they claimed for themselves. A long series of negotiations followed, the result of which was that the Emperor Nicephorus, in 812, acknowledged Charlemagne's title. The latter, immediately after his coronation in Rome, drew up a new oath of allegiance, which he required to be taken by the whole male population of the Empire. About this time, he entered into friendly relations with the famous Caliph, Haroun Alraschid of Bagdad. They sent embassies, bearing magnificent presents, to each other's courts, and at Charlemagne's request, Haroun took the holy places in Palestine under his special protection, and allowed the Christians to visit them.