Thus, language became the center of the conflict with the Frankish and German rulers and [[clergy]] as the Germans used Latin. With their liturgy denigrated as a "heretical Slavic Liturgy", Cyril and Methodius, accompanied by Clement, twice had to defend their liturgy before the Pope of Rome, first before Pope [[Adrian II of Rome|Adrian II]] and, again, before Pope [[John VIII of Rome|John VIII]] in 880, both who authorized its use.
During these years, the missionaries enjoyed the support of Prince Rastislav until 870. But, after Rastislav lost his realm to his nephew, prince Svyatopolk, who supported the German missionaries, the evangelization environment of the Slavic missionaries began to change as the Germans increasingly pressed the language issue. After the death of Methodius in 885 Pope [[Stephen V of Rome|Stephen V]] forced all the Slavonic speaking [[disciples]] of St. Methodius to leave Moravia, that is now part of the Czech Republic, after having subjecting them to trial and then dispersement.
Clement was among the disciples who were welcomed by the Bulgarian prince [[Boris I of Bulgaria|Boris]] to preach to his people in their language. As Bishop of Greater Macedonia, Clement received an appointment, in 886, to teach at Kutmichivitsa, a region in southwest Macedonia where he created separate schools for adults and for children. He organized a school at the princely court, which attained high esteem during the reign of Boris' son Simeon. St. Clement worked as a teacher until 893. In 893, St. Clement was named Bishop of Dremvitsa, or Velitsa.