What role did the invited foreigners play in the East Slavic lands?

We are talking in the 9th-11th centuries, at that time the Varangians and Greeks were foreigners in the East Slavic lands. The former were mainly engaged in trade along the trade route “From the Varangians to the Greeks”, which connected Scandinavia and the Black Sea, and they were also engaged in military affairs and took part in internecine wars, and fought with Byzantium or even entered the service of the emperors of Byzantium. Famous Varangians were: Askold, Dir, Asmud, Sveneld. The latter two even took part in the education of Prince Svyatoslav.

The Greeks were not only traders, but also church leaders after the adoption of Christianity, for example. the first metropolitan was Greek at the end of the 10th century.