names. By the Rusʹ–Byzantine Treaty (945) in 945, some signatories of the Rus had Slavic names while the vast majority had Norse names. The Chronicle presents the following origin myth for the arrival of Rus in the region of Novgorod: the Rus/Varangians 'imposed tribute upon the Chuds, the Slavs, the Merians, the Ves', and the Krivichians' (a variety of Slavic and Finnic peoples). From among Rurik's entourage it also introduces two Swedish merchants Askold and Dir (in the chronicle they are called "boyars", probably because of their noble class). The names Askold () and Dir () are Swedish; the chronicle says that these two merchants were not from the family of Rurik, but simply belonged to his retinue. Later, the Primary Chronicle claims, they conquered Kiev and created the state of Kievan Rusʹ (which may have been preceded by the Rusʹ Khaganate). Arabic sources Arabic-language sources for the Rus people are relatively numerous, with over 30 relevant passages in roughly contemporaneous sources. It can be difficult to be sure that when Arabic sources talk about Rus they mean the same thing as modern scholars. Sometimes it seems to be a general term for Scandinavians: when Al-Yaqūbi recorded Rūs attacking Seville in 844, he was almost certainly talking about Vikings based in Frankia. At other times, it might denote people other than or alongside Scandinavians: thus the Mujmal al-Tawarikh calls the Khazars and Rus 'brothers'; later, Muhammad al-Idrisi, Al-Qazwini, and Ibn Khaldun all identified the Rus as a sub-group of the Turks. These uncertainties have fed into debates about the origins of the Rus. Arabic sources for the Rus had been collected, edited and translated for Western scholars by the mid-20th century. However, relatively little use was made of the Arabic sources in studies of the Rus before the 21st century. This is partly because they mostly concern the region between the Black and the Caspian Seas, and from there north along the lower Volga and the Don. This made them less relevant than the Primary Chronicle to understanding European state formation further west. Imperialist ideologies, in Russia and more widely, discouraged research emphasising an ancient or distinctive history for Inner Eurasian peoples. Arabic sources portray Rus people fairly clearly as a raiding and trading diaspora, or as mercenaries, under the Volga Bulghars or the Khazars, rather than taking a role in state formation. The most extensive Arabic account of the