The Rus'-Byzantine War of 907 is associated in the Russian Primary Chronicle with the name of Oleg of Novgorod.

The chronicle implies that it was the most successful military operation of the Rus against the East Roman Empire.

Paradoxically, Greek sources do not mention it at all.

The Khazarian Jews of Kiev in the early tenth century write a Hebrew-language letter of recommendation on behalf of one of the members of their community, whose name is Yaakov bar Hanukkah.

The names of the Kievan Jews are of Turkic, Slavic and Hebrew origins, such as Hanukkah, Yehudah, Gostata and Kiabar.

(Scholars disagree as to whether these Jews were Israelites who had merely adopted local names, or whether their local names were a sign of their Turkic Khazarian origin.

The letter, known as the Kievan Letter, was discovered in 1962 by Norman Golb of the University of Chicago.)

Under Oleg, Kiev has become the center of a federation of strong points controlled by Varangian "dukes."

Oleg leads a large fleet from Kiev down the Dnepr River to the Black Sea.

Nicholas Mystikos may have become involved in the revolt of Andronikos Doukas.

He is deposed as patriarch on February 1, 907 and replaced by Euthymios.

Exiled to his own monastery, Nicholas regards his deposition as unjustified and involves Pope Sergius III in the dispute.

The new patriarch attempts a compromise by defrocking the offending priest but recognizing the marriage of Emperor Leo and Zoe.

In 907, Oleg obtains a treaty regulating the position of Russian merchants in Constantinople (which will be formally ratified in 911).

Many of the Rus' remain, becoming members of the emperor's Varangian (as the Greeks call the Swedish and Danish Vikings) guard.