The 128-year dynasty of the Komneni (1057 to 1185) was the last great
epoch of Byzantium, when the empire had to fend off Turkish and Norman
foes simultaneously. Starting with the extremely able Alexios I, and
unable now to count on help from the West, the Komneni played their
strategic cards very well. Though the dynasty ended in cruelty and
incompetence under Andronikos I (the Terrible), it fought a valiant
rear-guard action in keeping eastern Christendom alive. The Komnene
dynasty saw several changes in Byzantine military practice, such as the
adoption of heavy cavalry on the western model, the extensive use of
foreign mercenaries and the neglect of the navy (both of which were to
prove a huge and possibly fatal disadvantage). A chapter is devoted to
the famous Varangian Guard, which included many Saxons in exile
following the Norman conquest of England. The terrible defeat at
Myriokephalon in 1176 sealed the doom of the dynasty, preparing the way
for the conquest of Constantinople by the Fourth Crusaders.