 It has also been suggested that Helgu @-@ Oleg who waged war in the 940s was distinct from both of Rurik 's successors . 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 . Regrettably , the Primary Chronicle does not specify the relations between minor Rurikid princes active during the period , although the names Rurik , Oleg and Igor were recorded among the late @-@ 10th @-@ century and 11th @-@ century Rurikids . 
