In 1039 Byzantium was the most powerful empire in Europe and the Near East, controlling the Balkans south of the Danube and all of Asia Minor into Armenia and Syria. By 1079 it had become a politically unstable state half the size, menaced by powerful enemies on all sides. The History of Michael Attaleiates is our main source for this astonishing reversal, and offers a gripping narrative of the foreign and civil wars of those years. Attaleiates was a highly placed legal and military official of the empire with first-hand knowledge of the events he describes. He knew many of the...