 Complete the following phrase:  During the first half of this period 1185 the Byzantine Empire dominated the Balkans, and under the Komnenian emperors there was a revival of prosperity and urbanization; however, their domination of Southeastern Europe came to an end with a successful Vlach-Bulgarian rebellion in 1185, and henceforth the region was divided between the Byzantines in Greece, some parts of Macedonia, and Thrace, the Bulgarians in Moesia and most of Thrace and Macedonia, and the Serbs to the northwest. Eastern and Western churches had formally split in the 11th century, and despite occasional periods of co-operation during the 12th century, in 1204 the 