 Complete the following phrase:  Despite the treaty and the largely peaceful era that followed, the strategic position of the Bulgarian Empire remained difficult. The country was surrounded by aggressive neighboursthe Magyars to the north-west, the Pechenegs and the growing power of Kievan Rus to the north-east, and the Byzantine Empire to the south, which proved to be an unreliable neighbour. Bulgaria suffered several devastating Magyar raids between 934 and 965. The growing insecurity, as well as expanding influence of the landed nobility and the higher clergy at the expense of the personal privileges of the peasantry, led to the emergence of Bogomilism, a dualistic heretic sect that in the subsequent centuries spread to the Byzantine Empire, northern Italy and southern France cf. Cathars. To the south, the Byzantine Empire reversed the course of the ByzantineArab wars against the declining Abbasid Caliphate and in 965 discontinued the payment of the tribute, leading to sharp deterioration in their relations. In 968 the Byzantines incited Kievan Rus to 