Boris I Michail or Boris I Michael (Bulgarian Борис I Михаил)(d. May 2, 907) was the khan from 852 to 889 and first Christian ruler of Bulgaria. Michael became part of his name after his baptism in 864. He was son of Khan Presijan of Bulgaria.

Boris kept the borders of his country essentially unchanged with diplomacy and alliances with the Frankish king Charles the Bald, Prince Rostislav of Moravia, the Byzantine Emperor Michael III, and eventually King Louis the German even though suffering defeats. His armies often confronted Croatia and Serbia and the German monarchy as well. In 863 a peace treaty with the Byzantine Empire regained parts of Zagora for Bulgaria; in return, Boris I was obliged to terminate his alliance with the German kingdom and to adopt Christianity.

In 864 Boris was baptized in the palace in Pliska. Proselytism of his nobility was, however, carried out forcefully — Boris ordered the execution of over fifty nobles who kept their pagan belief. Yet other nobles came under the protection of Vladimir, the elder son of Boris and a pagan believer. Vladimir was mentioned in accompanying his father fighting against the Serbs before his father's baptism.

Boris sought the independence of the Bulgarian Church, keeping the middle ground between Pope Nicholas I and the religion, law, politics, customs and personal faith. Catholic bishops and Byzantine priests were allowed to baptize and bless the people. In 870 the Bulgarian Church was given autonomy from the Byzantine Church.

In 893 Boris retired to a monastic life and was succeeded by his son Vladimir. Supported by pagan nobles, Vladimir reestablished paganism but was dethroned by Boris, who came out of retirement and, according to some traditions, blinded Vladimir. Simeon, his other son, then assumed the throne and continued his father's work.

Boris was familiar with the work of Cyril and Methodius, the inventors of the Slavic alphabet, as early as 881-882. Two of their disciples, Clement and Naum, set up educational centers in Pliska and in Kutmichevista (Macedonia) to further the development of Slavonic letters and liturgy. The alphabet developed by Cyril and Methodius came to be known as the Cyrillic alphabet and was adopted by other Slavic peoples.

He passed away as a monk.

Resources

• http://www.bulgaria.com/history/rulers/boris1.html