The head of the Premyslid Czechs who dominated the environs of Prague, Borivoj in c. 870 declared himself kníže (later translated by German scholars as 'Duke') of the Czechs (Bohemians). Borivoj was recognised as such by his overlord Svatopluk of Great Moravia who dispatched Bishop Methodius to begin the conversion of the Czechs to Christianity. Borivoj and his wife Ludmilla were baptised somewhere in the 880s and the latter especially became an enthusiastic evangelist, although the religion failed to take root among Borivoj's subjects.
As with most of the early Bohemian rulers, Borivoj is a shadowy figure and exact dates and facts for his reign can never be considered as completely reliable. Few books on early medieval Czech history exist in English and most information can be best located in Czech works or websites.