The reference is to the Kievian Rus of which Novgorod was the second largest city. Oleg of Novgorod conquored Kiev in the early 10th century, and became ruler of the Kievian Rus, consolidating it into a “state”, previously a looser domain, and is often considered the founder of the “state”, though the Rus predated it by around a century. Novgorod remained the second largest city. Lots of legend here. Of course these were Norse, not slavs. Rus which evolved to Russia generally translated as Swedish or northmen. As elsewhere the Norse population becoming absorbed. Both are reasonably termed “birthplace”, though culturally Russia is Slavic not Norse, thus both incorrect in a cultural sense.
Needless to say what Ha'aertz describes as a minority demonstrates the ingratitude of Israel to the US.