The earliest records that can be said to give a fairly certain clue as to the presence of soldiery from the Russian/Norse territories are from the reign of Theophilus (829–42). During his tenure of the throne bands of Norse warriors entered Southern Russia and penetrated as far as the Black Sea, becoming a threat to the city of Cherson, the capital of the Chersonese theme of the Empire. The city called for help from the Emperor, who sent a garrison and a force to raise and man a fortress at Sarkel on the lower Don, in the lands of his Khazar allies, the intention being to protect both them and the imperial frontier.

These activities by the Imperial authorities probably led to a desire on the part of the Viking chieftains to make closer contacts with Byzantium. One piece of evidence suggests that they were certainly at the court in 836–39 – this is the passage in the Annales Bertiniani composed by Bishop Prudentius of Troyes. Prudentius tells of the arrival of an embassy from Theophilus at the court of Louis the Pious, who received them at Ingelheim on 18 May 839. The leader of the mission was Theodore Babutzikios, who had died en route, but among the Greek emissaries were men from a nation called Rhos, whose king, Chacanos, had sent them on a mission of friendship to Byzantium.