ABSTRACT
This chapter discusses many possible definitions and indicators and many theories on empires. The empires or imperial communities of medieval Europe were engaged in imperialistic politics to a lesser extent than the empires of the nineteenth century. The impact that medieval imperial communities had on their neighbour states was relatively low and was manifest in border campaigns and raids, marriages, military support, and donations of money and ranks. The Byzantine Empire was maintained by an imperial community capable of integrating many other powers into its sphere of control. In the tenth century, intensified contacts between the Byzantine emperors and the Hungarian rulers were established and their relations tightened quickly. The papal state was one of the inter-imperial powers lying outside East Central Europe but placed between the Western and the Eastern Roman empires and resembled some of the features of the Hungarian case.
