Complex sentence: Most of Albania became part of the First Empire in the early 840s, during the reign of Khan Presian, but some coastal towns such as Durrës remained in the hands of the Byzantines for most of that period.
Split into simpler sentences: Most of Albania became member of the First Empire in the early 840s, during the era of Khan Presian. But some coastal towns such as Durrës remained in the hands of the Byzantines for most of that period.