This traditional dating has been challenged by some historians, who point out that it is inconsistent with such other sources as the Schechter Letter, which mentions the activities of a certain khagan HLGW (Hebrew: הלגו usually transcribed Helgu.

The nature of Oleg's relationship with the Rurikid ruling family of the Rus', and specifically with his successor Igor of Kiev, is a matter of much controversy among historians.

Having fixed his shield to the gate of the imperial capital, Oleg won a favourable trade treaty, which eventually was of great benefit to both nations.

[18] Scholars have contrasted this dating scheme with the "epic" reigns of roughly thirty-three years for both Oleg and Igor in the Primary Chronicle.

The Schechter Letter,[26] a document written by a Jewish Khazar, a contemporary of Romanus I Lecapenus, describes the activities of a Rus' warlord named HLGW (Hebrew: הלגו), usually transcribed as "Helgu".

[27] For years many scholars disregarded or discounted the Schechter Letter account, which referred to Helgu (often interpreted as Oleg) as late as the 940s.

[31] Of particular interest is the fact that the Schechter Letter account of Oleg's death (namely, that he fled to and raided FRS, tentatively identified with Persia,[32] and was slain there) bears remarkable parallels to the account of Arab historians such as Ibn Miskawayh, who described a similar Rus' attack on the Muslim state of Arran in the year 944/5.

Furthermore, scholars have pointed out that if Oleg succeeded Rurik in 879 (as the East Slavic chronicles assert), he could hardly have been active almost 70 years later, unless he had a life-span otherwise unheard of in medieval annals.

He could have been one of the "fair and great princes" recorded in the Russo-Byzantine treaties of 911 and 944 or one of the "archons of Rus" mentioned in De administrando imperio.

[citation needed] Georgy Vernadsky even identified the Oleg of the Schechter Letter with Igor's otherwise anonymous eldest son, whose widow Predslava is mentioned in the Russo-Byzantine treaty of 944.