Ukrainian i/juːˈkreɪniən/ (українська мова ukrayins'ka mova, pronounced an East Slavic language. It is the official state language of Ukraine and first of two principal languages of Ukrainians; it is one of the three official languages in the unrecognized state of Transnistria, the other two being Romanian and Russian. Written Ukrainian uses a variant of the Cyrillic script (see Ukrainian alphabet). History During the Khazar period, the territory of Ukraine, settled at that time by Iranian (post-Scythian), Turkic (post-Hunnic, proto-Bulgarian), and Uralic (proto-Hungarian) tribes, was progressively Slavicized by several waves of migration from the Slavic north. Finally, the Varangian ruler of Novgorod, called Oleg, seized Kiev (Kyiv) and established the political entity of Rus'. Some theorists see an early Ukrainian stage in language development here; others term this era Old East Slavic or Old Ruthenian/Rus'ian. Shelest period The Communist Party leader Petro Shelest pursued a policy of defending Ukraine's interests within the Soviet Union. He proudly promoted the beauty of the Ukrainian language and developed plans to expand the role of Ukrainian in higher education. He was removed, however, after only a brief tenure, for being too lenient on Ukrainian nationalism. LITERATURE The literary Ukrainian language, which was preceded by Old East Slavic literature, may be subdivided into three stages: old Ukrainian (12th to 14th centuries), middle Ukrainian (14th to 18th centuries), and modern Ukrainian (end of the 18th century to the present). Much literature was written in the periods of the old and middle Ukrainian language, including legal acts, polemical articles, science treatises and fiction of all sorts.