When the Varangians first appeared in Constantinople (the Paphlagonian expedition of the Rus' in the 820s and the Siege of Constantinople in 860), the Byzantines seem to have perceived these people they called the "Rhos" () as a different people from the Slavs. At least no source says they are part of the Slavic race. Characteristically, Pseudo-Simeon and Theophanes Continuatus refer to the Rhos as "dromitai" (Δρομῖται), a word related to the Greek word meaning "a run", suggesting the mobility of their movement by waterways.