In the 9th century, Swedish Vikings, known as the Varangians, ventured eastward, impacting the territories of the East Slavs. According to the Primary Chronicle, these Vikings imposed tribute on Slavic and Finnic tribes by 859. However, in 862, the local tribes rebelled, expelling the Varangians and attempting to govern themselves. Yet, facing internal disorder, they invited the Varangian Rus' back to rule over them. Three Viking brothers—Rurik, Sineus, and Truvor—responded, with Rurik establishing control in Novgorod. After the deaths of his brothers, Rurik became the sole ruler, founding the Rurikid dynasty.
Two of Rurik's men, Askold and Dir, then set out toward Constantinople (Tsargrad). Along the way, they captured Kiev, which was under Khazar control, establishing their authority over the region. By 863-866, Askold and Dir led a naval expedition to attack Constantinople, surprising the Byzantines and devastating the surrounding areas. Although they never breached the city itself, this marked the first significant encounter between the Rus' and Byzantium, which led to missionary efforts from Constantinople to convert the Rus' and Slavs.
Modern scholars often view these events, particularly the invitation to rule, as a later fabrication by Orthodox chroniclers to legitimize Viking rule and the Rurikid dynasty's origins. Nevertheless, these stories capture the significant role Swedish Vikings played in shaping early East Slavic political structures and in their interactions with Byzantium.