"boris" is first found in written records in the case of the bulgarian ruler prince boris i (852–889), who adopted christianity in 864 ad and introduced it to his people. his name came to be known in europe in relation to this particular act. moreover, after his death in 907 ad he was proclaimed the first bulgarian saint, and traces of his orthodox sainthood during this period can be found as far away as catholic ireland. the patriarchate of constantinople recognized the canonization of st. boris in 923 ad. however, prince boris was purportedly not a slav. he descended from the bulgars. among the bulgars the name was known in its two forms: "boris" and "bogoris".