Boris kept the borders of his country essentially unchanged with diplomacy even though suffering defeat. His armies often fought Croatia and Serbia and the German monarchy as well. His alliance with the Frankish king Charles the Bald, Prince Rostislav of Moravia, the Byzantine Emperor Michael III, and eventually King Louis the German kept Bulgarian borders intact. In 863 A peace treaty with 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 were, 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 Patriarch of Constantinople. His special delegation to the Pope carried a list of 115 questions and returned with the famous 106 answers concerning the essence of 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.
| Preceded by: Malamir and possibly Presian |
List of Bulgarian monarchs |
Succeeded by: Valdimir |