The long-lasting peace with the Empire established by Simeon's father is about to end.

A conflict arises when Emperor Leo VI the Wise, allegedly acting under pressure from his mistress Zoe Zaoutzaina and her father Stylianos Zaoutzes, moves the marketplace for Bulgarian goods from Constantinople to Thessaloniki, where the Bulgarian merchants are heavily taxed.

The Bulgarians seek the protection of Simeon, who in turn complains to Leo.

However, the emperor ignores his embassy.

Forced to take action, Simeon invades the Empire from the north in the autumn of 894, meeting with little opposition due to the concentration of most imperial forces in eastern Anatolia to counter Arab invasions.

Informed of the Bulgarian offensive, the surprised Leo sends an army consisting of guardsmen and other military units from the capital to halt Simeon, but his troops are routed somewhere in the theme of Macedonia.

The Bulgarians take most of the Khazar mercenary guardsmen prisoners and kill many archons, including the army's commander.

However, instead of continuing his advance to the capital, Simeon quickly withdraws his troops to face a Magyar invasion from the north.

Bulgarian historians will later call these events "the first trade war in medieval Europe.”