Belerus Is Polotsk

as suggested by such a name as POLOTSK : "POL + SK"

Less from migrations, and more via conquest and redefinition

Read the history:

http://en.wikipedia.org/wiki/Polans_%28eastern%29

According to chronicalized legends, the largest cities of the eastern Polans were Kiev, Pereyaslav, Rodnia, Vyshhorod, Belgorod (now Bilohorodka village at the Irpin river) and Kaniv. In the 10th century, the term "Polans" was virtually out of use and exchanged for "Rus", with Polans as a tribe being last mentioned in a chronicle of 944.<sup>[3]

http://en.wikipedia.org/wiki/Principality_of_Polotsk</sup>



http://en.wikipedia.org/wiki/Polock_Voivodship


http://en.wikipedia.org/wiki/Polesia