According to early sources such as the sagas, especially Heimskringla, the Swedes were a powerful tribe whose kings claimed descendence from the god Freyr.
During the Viking Age they constituted the basis of the Varangian subset, the Norsemen that travelled eastwards (see Rus' people).
[2][3][4] According to the prevalent theory, the name Rus', like the Proto-Finnic name for Sweden (*roocci),[5] is derived from an Old Norse term for "the men who row" (rods-) as rowing was the main method of navigating the rivers of Eastern Europe, and that it could be linked to the Swedish coastal area of Roslagen (Rus-law) or Roden, as it was known in earlier times.
Swedish men left to enlist in the Byzantine Varangian Guard in such numbers that a medieval Swedish law, Västgötalagen, from Västergötland declared no one could inherit while staying in "Greece"—the then Scandinavian term for the Byzantine Empire—to stop the emigration,[9] especially as two other European courts simultaneously also recruited Scandinavians:[10] Kievan Rus' c. 980–1060 and London 1018–1066 (the Þingalið).
As the dominions of the Swedish kings grew, the name of the tribe could be applied more generally during the Middle Ages to include also the Geats.
In modern North Germanic languages, the adjectival form svensk and its plural svenskar have replaced the name svear and is, today, used to denote all the citizens of Sweden.
A closely similar form, Swēon, is found in Old English and in the Gesta Hammaburgensis ecclesiae pontificum of Adam of Bremen about the Hamburg-Bremen archbishops who are denoted Sueones.
Most scholars agree that Suiones and the attested Germanic forms of the name derive from the same Proto-Indo-European reflexive pronominal root, *s(w)e, as the Latin suus.
The same root and original meaning is found in the ethnonym of the Germanic tribe Suebi, preserved to this day in the name Schwaben (Swabia).
A 13th century Danish source in Scriptores rerum danicarum mentions a place called litlæ swethiuthæ, which is probably the islet Sverige (Sweden) in Saltsjön in eastern Stockholm.
Their territories also very early included the provinces of Västmanland, Södermanland and Närke in the Mälaren Valley which constituted a bay with a multitude of islands.
Some dispute whether the original domains of the Suiones really were in Uppsala, the heartland of Uppland, or if the term was used commonly for all tribes within Svealand, in the same way as old Norway's different provinces were collectively referred to as Nortmanni.
What strikes the commentators of this text is that this large tribe is unknown to posterity, unless it was a simple misspelling or misreading of Illa Svionum gente.
The poem describes Swedish-Geatish wars, involving the Swedish kings Ongentheow, Ohthere, Onela and Eadgils who belonged to a royal dynasty called the Scylfings.
The third Anglo-Saxon source is Alfred the Great's translation of Orosius' Histories, with appended tales of the voyages of Ohthere of Hålogaland and Wulfstan of Hedeby, who in the 9th century described the Sweon and Sweoland.
Ohthere's account is limited to the following statement about Swēoland: Wulfstan only mentions a few regions as being subject to the Sweons (in translation): The Annales Bertiniani relate that a group of Norsemen, who called themselves Rhos visited Constantinople around the year 838.
Dealing with Scandinavian affairs, Adam of Bremen relates in the 11th century Gesta Hammaburgensis ecclesiae pontificum that the Sueones had many wives and were severe on crime.