Gerard Friell & Stephen Williams 
Rome that Did Not Fall [PDF ebook] 
The Survival of the East in the Fifth Century

The Rome that Did Not Fall provides a well-illustrated, comprehensive narrative and analysis of the Roman empire in the east, charting its remarkable growth and development which resulted in the distinct and enduring civilization of Byzantium. It considers:* the fourth century background* the invasions of Attila* the resources of the east* the struggle for stability* the achievements of Anastasius.