However, Boris' son Tsar Simeon put a bit more distance between his realm and that of the Byzantines by establishing the independence of the Bulgarian Patriarchy. Under Simeon (893-927), the Bulgarian Kingdom reached its greatest power and size. Sometimes called the Kingdom of Three Seas, it stretched from the Black Sea in the east, to the Aegean in the south and to the Adriatic at the western edge of the Balkan Peninsula. The capital was moved to Preslav, also situated in the north-east.
Simeon encouraged learning and education, and Slavic culture flourished. Brothers Cyril and Methodius from Thessaloniki (now in present-day Greece) are credited with inventing the earliest form of the Cyrillic alphabet, called Glagolithic, in order to best represent the sounds of the Slavic language. Their student, Kliment Ohridski, further developed the alphabet, which he named after Cyril, and founded the first Slavic university on the shores of Lake Ohrid, in present-day Macedonia.
Learning centres in Preslav and Ohrid created works of literature in Slavic, which was the first time in Europe that one of the traditionally sacred tongues of Hebrew, Latin and Greek were not used.
Simeon renewed the fight with the Byzantines, however, and coupled with internal discontent among the nobles, or boyars, the Kingdom of the Three Seas soon shrank. Serbia won back its independence in 933, and under the next tsars the Bulgarian Kingdom steadily lost land, including much of the eastern territory, once more to the Byzantines. The Bulgarians were finally left with a small holding called the Western Kingdom, with an administrative centre at Ohrid. Tsar Samuel (980-1014) won back a portion of the lost lands, but in a decisive battle in 1014 at Strumitsa, his army was defeated by the Byzantines. Emperor Basil II had the eyes of some 14,000 Bulgarian soldiers put out, with a few left with one eye in order to guide the maimed force back to Samuel. Legend has it that the Tsar died of a broken heart upon seeing the blinded men, and even Ohrid fell four years later.
