Known as Leo the Wise, the second Macedonian emperor’s reign was one of internal success and external setback. Almost immediately Leo distanced himself from Basil's policies. One of his first acts was to rebury Michael III, suggesting that whatever doubts Basil had about Leo's parentage, Leo himself was sure. He also deposed Photios, raising his brother Stephen to the patriarchate. Leo's reign saw the beginning, in 894, of the long struggle with Symeon of Bulgaria. Symeon defeated the Byzantines in 896, forcing Byzantium to pay tribute as the price of peace. In Sicily Taormina fell in 902, marking the end of the Byzantine province created by Justinian I in the early sixth century. Closer to home, Leo of Tripoli led his fleet to sack Thessloniki, the second city of the empire, in 904. Although there were successes on the eastern border, Byzantine attacks on Crete and Cyprus failed disastrously. After an absence of forty–seven years the Russians attacked Constantinople in 907 and 911, eventually being bought off with the grant of trading privileges. The reign of Leo VI, however, inaugurated the relationship between the imperial family and the Phokas family, which would come to dominate the military leadership and direct the forces of expansion in the second half of tenth century.
Leo began the process of codification and collection that would mark what has been called the Macedonian Renaissance. From orders of precedence (the Kletorologion of Philotheos) to Constantinopolitan guilds (Book of the Eparch), Roman law (the Basilika) to military tactics (the Taktika), Leo’s efforts demonstrate the wide range of imperial interests. The works published during his reign and in his name were nominally interested in updating past conventions to the realities of the present, and serve to underline and, at times, exaggerate the relationship of Byzantium with its past.
One of the most dramatic events of his reign was the Tetragamy Controversy. Heirless with his first three wives, he conceived a son, Constantine, with his concubine Zoe, but met resistance from Patriarch Nicholas I Mystikos when he attempted to marry for a fourth time and thus legitimize the child. The controversy continued from 906 until the Tomos of Union in 920, long after Leo's death. Ranging far beyond the subject of Constantine's legitimacy, it encompassed a struggle between the factions of patriarchs Nicholas and Euthymios, the legitimacy of their tenures, and, not least important, the validity of their respective ecclesiastical appointments. Leo appealed to the pope, reopening the argument about papal superiority over the Byzantine Church.
Leo’s seals follow the pattern laid down by Basil I. Christ is shown on the obverse while Leo and his brother Alexander are depicted on the obverse holding a labarum between them. Leo as the senior emperor is shown bearded, while Alexander is depicted as a beardless youth. For more seals of Leo's family see the Macedonian Dynasty in the Dynasties of Empire section.