Nicholas Mystikos has become the leading member of the regency for the young emperor, and as such has to face the advance of Simeon on Constantinople, who, coveting the imperial crown, has severely defeated the imperial armies.

Nicholas negotiates a peaceful settlement, crowns Simeon emperor of the Bulgarians in a makeshift ceremony outside Constantinople, and arranges for the marriage of Simeon's daughter to Constantine VII.

This unpopular concession, which looks like a betrayal of the empire to the Bulgarians, undermines his position, and by March 914, Zoe Karbonopsina has overthrown Nicholas and replaces him as foremost regent.

She revokes the agreement with Simeon, prompting the renewal of hostilities with Bulgaria.