Knyaz (prince) Boris is the son of the ruler Presian. In 865 he made peace with Constantinople and, together with his family, converted to Christianity, taking the name Mihail. In search of what is best for the Bulgarian clergy during the conversion of the people, Prince Boris conducted negotiations with Rome and with Constantinople, and managed to attain autocephaly for the Bulgarian church and to make Bulgaria part of Christian civilization. He involved the disciples of the Slavic enlighteners, saints Cyril and Methodius in the process, thus laying the foundations of Bulgarian literature.

In 889 he became a monk. His heir Vladimir attempted to reinstate paganism, and Boris took power once again, putting his other son, Simeon on the throne. He then returned to the monastery where he died on 2 May, 907.