The Byzantine Empire and Russia. The Patzinak problem
In the time of the Macedonian dynasty very animated relations developed between Russia and Byzantium. According to the Russian chronicler, during the reign of Leo VI the Wise in the year 907 the Russian Prince Oleg appeared at the walls of Constantinople with numerous vessels. After pillaging the environs of the capital and killing a large number of people, Oleg forced the Emperor to initiate negotiations and reach a final agreement. Although no sources, Byzantine, western, or eastern, known up to recent times, refer to this expedition or to the name of Oleg, this account of the Russian chronicler, touched with legendary detail as it is, is based on actual historical events. It is very probable that this preliminary agreement of 907 was confirmed in 911 by a formal treaty which, also according to the old Russian chronicler, provided important trade privileges for the Russians.
The famous history of Leo the Deacon, an invaluable source for the second half of the tenth century, has an interesting passage which does not usually receive due consideration, although at present it ought to be viewed as the sole hint at Oleg's treaties found in Greek sources. This hint is the threat to Sviatoslav which Leo the Deacon put into the mouth of John Tzimisces: I hope you have not forgotten the defeat of your father Igor who, having scorned the sworn agreements (τὰς ἐνόρκους σπονδάς), came by sea to the imperial city with a great army and numerous vessels. These sworn agreements made with the Byzantine Empire before Igor's time must have been the agreements of Oleg reported by the Russian chronicler. It might be interesting to compare the reference just given with the accounts found in Byzantine sources of the presence of Russian subsidiary troops in the Byzantine army from the early tenth century, and with the corresponding clause of the treaty of 911 (as given in the Russian chronicle), which permits the Russians, if they should so desire, to serve in the army of the Byzantine Emperor.