”Numerous scholars identified Rorik＜,＞・・a Danish Viking, who ruled over parts of Friesland between 841 and 873, conquering Dorestad and Utrecht in 850＜,who＞ swore allegiance to Louis the German in 873＜and who＞ was born in Denmark around 800＜,＞ died at some point between 873 and 882・・＜,＞with Rurik, the founder of the Rurikid dynasty. The suggestion is based on the disappearance of Rorik from Frankish chronicles during the 860s, consistent with the appearance of Rurik in Novgorod in 862, but inconsistent with his remaining in power there until 879.
The first identification to this effect was made by Hermann Hollmann in 1816. He stressed the importance of the locality of Rustringen, in Lower Saxony, as the possible origin of Rurik. In 1836, Friedrich Kruse also supported such a view. The hypothesis was revived strongly by N. T. Belyaev in 1929.
Such an identification is not conclusive, and does not appear to have support from the majority of scholars. Yet there are a number of prominent Russian academics, such as A. N. Kirpichnikov, Boris Rybakov, Dmitry Machinsky, and Igor Dubov, who have supported this identification to some extent.”
”During the historical debates of the 20th century, the key evidence for the mainstream view that Scandinavian migrants had an important role in the formation of Kievan Rus’ emerged as the following:
Notwithstanding other suggestions, the name Rus’ can readily be interpreted as originating in Old Norse.
The personal names of the first few Rus’ leaders are etymologically Old Norse, from Rurik (from Old Norse Hrærekr) down to Olga of Kiev (from Old Norse Helga). (From Olga’s son Sviatoslav I of Kiev onwards, Slavic names take over.)
The list of cataract＜（瀑布）＞s on the Dnieper listed by Constantine VII in his De Administrando Imperio as belonging to the language of the Rhos can most readily be etymologised as Old Norse.
The Annals of St. Bertin account of the Rhos for 839 has them identify themselves as sueoni (Swedes).
13th-century Icelandic historiography portrays close connections between the 11th-century rulers of Rus’ and Scandinavian dynasties in England and Norway.
In the 21st century, analyses of the rapidly growing range of archaeological evidence further noted that high-status 9th- to 10th-century burials of both men and women in the vicinity of the Upper Volga exhibit material culture largely consistent with that of Scandinavia (though this is less the case away from the river, or further downstream). This has been seen as further demonstrating the Scandinavian character of elites in Old Rus’.
It is also agreed, however, that ancestrally Scandinavian Rus’ aristocrats, like Scandinavians elsewhere, swiftly assimilated culturally to a Slavic identity: in the words of F. Donald Logan, “in 839, the Rus were Swedes; in 1043 the Rus were Slavs”.”