Slavs
Slavs are the largest ethno-linguistic group in Europe. Present-day Slavic people are classified into East Slavs (chiefly Belarusians, Russians, Rusyns, and Ukrainians), West Slavs (chiefly Czechs, Kashubs, Moravians, Poles, Silesians, Slovaks and Sorbs), and South Slavs (chiefly Bosniaks, Bulgarians, Croats, Macedonians, Gorani, Pomaks, Montenegrins, Serbs and Slovenes).
Ukrainians
Differentiation between separate East Slavic groups began to emerge in the later medieval period, and an East Slavic dialect continuum developed within the Polish–Lithuanian Commonwealth, with the Ruthenian language emerging as a written standard. The active development of a concept of a Ukrainian nation and a Ukrainian language began with the Ukrainian National Revival in the early 19th century. In the Soviet era (1917–1991), official historiography emphasized "the cultural unity of 'proto-Ukrainians' and 'proto-Russians' in the fifth and sixth centuries".