The early origins of the Carpatho-Rusyns are complex. They were not, as is often asserted, exclusively associated with Kievan Rus’, from which it is said their name Rusyn derives.
Rather, the ancestors of the present-day Carpatho-Rusyns are descendants of:
(1) early Slavic peoples who came to the Danubian Basin with the Huns and Avars;
(2) the White Croats;
(3) the Rusyns of Galicia and Podolia;
(4) rusynized Vlachs from the southeast.
Moreover, because Carpatho-Rusyns received Christianity over a century earlier than Kievan Rus’, it is likely that they used the name Rusyn and were called by others Rusyns (Latin: Rutheni) even before the arrival of subsequent Rusyn migration from the north and east. On the other hand, because their Eastern-rite Christian religion derived from Orthodox Byzantium, Carpatho-Rusyns maintained cultural and religious ties with the Kievan Rus’ principality of Galicia to the north, Moldavia/Transylvania to the south, and with other Orthodox lands (central Ukraine and later Russia) farther east. Carpathian Rus’ was not, however, under the political hegemony of Kievan Rus’ or of any other East Slavic political entity during the Middle Ages or at any time until the second half of the twentieth century. Instead, Carpathian Rus’ has historically been within political and cultural spheres that are firmly part of central Europe. By the second half of the eleventh century Rusyn-inhabited lands on the southern slopes of the Carpathians came under the control and were incorporated into the *county administrative structure of the kingdom of Hungary.
… etc. in http://www.rusyn.org