 Following the Muslim conquests of the 7th century, the Arab – Byzantine conflict had featured constant raids and counter-raids along a relatively static border roughly defined by the line of the Taurus and Anti-Taurus Mountains. Until the 860s, superior Muslim armies had placed the Byzantines on the defensive. Only after 863, with the victory in the Battle of Lalakaon, did the Byzantines gradually regain some lost ground against the Muslims, launching ever-deeper raids into Syria and Upper Mesopotamia and annexing the Paulician state around Tephrike (now Divriği). Furthermore, according to historian Mark Whittow, "by 912 the Arabs had been pinned back behind the Taurus and Anti-Taurus", encouraging the Armenians to switch their allegiance from the Abbasid Caliphate to the Empire, in whose service they entered in increasing numbers. The revival of Byzantine power was further facilitated by the progressive decline of the Abbasid Caliphate itself, particularly under al-Muqtadir (r. 908 – 932), when the central government faced several revolts. In the periphery of the Caliphate, the weakening of central control allowed the emergence of semi-autonomous local dynasties. In addition, after the death of the Bulgarian Tsar Simeon in 927, a peace treaty with the Bulgarians allowed the Empire to shift attention and resources to the East.
