Also found in: Dictionary, Wikipedia.
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 ISimeon I,
c.863–927, ruler (893–927) and later first czar of Bulgaria. He was placed on the throne by his father, Boris I, who had returned from a monastery to depose his first son, Vladimir (reigned 889–93), for attempting to reintroduce paganism.
..... Click the link for more information. .
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.