Byzantium's enemy to the north was Simeon, the Bulgar ruler. Simeon was educated
in Constantinople, learned to speak and write greek and was able to read
Aristoteles and Demosthenis from prototype. But later he became an ardent enemy of the Greek
Empire. Those years Bulgars and Slavs were christianized by
through missions lead by Cyril and Methodios.
Hostilities arose out of a trade dispute in 894, and the Byzantines, aided by the Magyars of the Danube-Dnieper region, forced Simeon to agree to a truce. With the help of the nomadic Pechenegs, however, Simeon in 896 took revenge on the Byzantines, forcing them to pay an annual tribute to the Bulgars. Leo was incapable to face the enemies of the state, because his main interest was literature and poetry and not the proper organization of Byzantine army.
During Leo's reign the Russian prince Oleg sailed to Constantinople in 907. Russian historian Nestor wrote that 2000 vessels which looked more to canoes than to ships, attacked the Queen of the cities. Leo was proved again incapable to lead his army and Russians obtained a treaty regulating the position of Russian merchants in Byzantium. This treaty was formally ratified in 911.
Because of his anxiety for a male heir Leo married four times, thus incurring the censure of the church. According to ecclesiastical law a man should not get married more than three times. In addition to completing the canon of laws, he wrote several decrees (novels) on a wide range of ecclesiastical and secular problems. He also wrote a funeral panegyric on his father, liturgical poems, sermons and orations, secular poetry, and military treatises. Leo's image is in a mosaic over the central door of Hagia Sophia. He died May 11 912 and he was succeedeed by his son Constantine Porfhyrogennetus the 7th.
Paparighopoulos Konstantinos, Istoria tou Ellinikou Ethnous