Slavs
Slavs can be further grouped by religion. Orthodox Christianity is practiced by the majority of Slavs. The Orthodox Slavs include the Belarusians, Bulgarians, Macedonians, Montenegrins, Russians, Serbs, and Ukrainians and are defined by Orthodox customs and Cyrillic script as well as their cultural connection to the Byzantine Empire (Serbs also use Latin script on equal terms). Their second most common religion is Roman Catholicism. The Catholic Slavs include Croats, Czechs, Kashubs, Moravians, Poles, Silesians, Slovaks, Slovenes, and Sorbs and are defined by their Latinate influence and heritage and connection to Western Europe. There are also substantial Protestant and Lutheran minorities especially amongst the West Slavs, such as the historical Bohemian (Czech) Hussites.
History of Ukraine
This term seems to have been synonymous with the land of Rus' propria—the principalities of Kiev, Chernigov and Pereyaslav. The term, "Greater Rus'" was used to apply to all the lands of entire Kievan Rus, including those that were not just Slavic, but also Uralic in the north-east portions of the state. Local regional subdivisions of Rus' appeared in the Slavic heartland, including, "Belarus'" (White Russia), "Chorna Rus'" (Black Russia) and "Cherven' Rus'" (Red Russia) in northwestern and western Ukraine.