Boris I

Boris I, d. 907, khan [ruler] of Bulgaria (852–89). Baptized in 864, he introduced Christianity of the Byzantine rite among the Bulgarians. There followed a rivalry between Rome and Constantinople for the loyalty of the Bulgarian church. In 889, Boris abdicated and retired to a monastery. His son was called Czar Simeon I.

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Boris I

 orig. Mikhail

(died May 2, 907, Preslave, Bulg.) Khan of Bulgaria (852–89). He resolved to use Christianity to unite his ethnically divided country, and an unsuccessful war with the Byzantines led to his baptism in the Orthodox faith (864). Boris's attempt to enforce mass baptism set off a pagan rebellion, which he quelled, and he helped establish the Bulgarian church. He sponsored missionaries to foster Slavic learning and the use of the Old Church Slavic language. He abdicated in 889 to become a monk but returned to drive his reactionary son Vladimir from the throne. After installing another son, Simeon I, as khan, Boris went back to his monastery. He was later made an Orthodox saint.

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Boris I 

Died May 2, 907. Prince of Bulgaria from 852 to 889. He succeeded in strengthening the power of the prince. In 864 (865) he introduced Christianity in the Byzantine (orthodox) form. He strove to achieve independence for the church and, by maneuvering between Rome and Constantinople, brought about the institution of an archbishopric in Bulgaria in 879–880. In 886 he invited the pupils of Methodius—Clement, Nahum, and others—to Bulgaria. In 889 he handed over the throne to his son Vladimir and entered a monastery, assuming the name Mikhail.