Руский=росийский
С. Плохий в своей работе «Plokhy, Serhii. The Cossacks and Religion in Early Modern Ukraine. Oxford University Press, 2002. S.320,321» переводит слова руский (русский) и росийский из источников одним словом Rus’:
Another important motif that also originated long before Pereiaslav and was fully expressed during Buturlin’s embassy to Ukraine was the representation of Kyiv as a former tsarist/princely capital. This motif made its appearance in Metropolitan Sylvestr Kosov’s address to Buturlin. Kosov noted particularly that Kyiv was the ‘very first seat of Rus’ [ruskii ] piety’ (седалище первейшее благочестие рускаго), and Volodymyr ‘the first pious Rus’ [rosiiskii ] grand prince’ (первым благочестивым росийским великим князем). According to Buturlin’s diplomatic report, both Khmelnytsky and Vyhovsky referred to Tsar Aleksei Mikhailovich as a ‘relative’ of Grand Prince Volodymyr. Kyivan burghers wrote to the tsar in May 1654 about the bequests made to Kyiv, ‘as their Rus’ capital city’ (яко столечному граду своєму росийскому), by the ancient princes of Kyiv. And in his speech before the tsar in the autumn of that year, Archpriest Maksym Fylymonovych, touching on the decline of Kyiv, spoke of its earlier burgeoning: ‘during the rule of the Rus’ grand princes (за княження великих князей русских), the most eminent city of Kyiv was the natural mother of cities, the mother of churches, the abode of God, and was called the second Jerusalem’.
Another important motif that also originated long before Pereiaslav and was fully expressed during Buturlin’s embassy to Ukraine was the representation of Kyiv as a former tsarist/princely capital. This motif made its appearance in Metropolitan Sylvestr Kosov’s address to Buturlin. Kosov noted particularly that Kyiv was the ‘very first seat of Rus’ [ruskii ] piety’ (седалище первейшее благочестие рускаго), and Volodymyr ‘the first pious Rus’ [rosiiskii ] grand prince’ (первым благочестивым росийским великим князем). According to Buturlin’s diplomatic report, both Khmelnytsky and Vyhovsky referred to Tsar Aleksei Mikhailovich as a ‘relative’ of Grand Prince Volodymyr. Kyivan burghers wrote to the tsar in May 1654 about the bequests made to Kyiv, ‘as their Rus’ capital city’ (яко столечному граду своєму росийскому), by the ancient princes of Kyiv. And in his speech before the tsar in the autumn of that year, Archpriest Maksym Fylymonovych, touching on the decline of Kyiv, spoke of its earlier burgeoning: ‘during the rule of the Rus’ grand princes (за княження великих князей русских), the most eminent city of Kyiv was the natural mother of cities, the mother of churches, the abode of God, and was called the second Jerusalem’.