defence-in-depth strategy or continued the same posture of "forward defence" as in the early Principate. Many elements of the late army's defence posture were similar to those associated with forward defence, such as a looser forward location of forts, frequent cross-border operations, and external buffer-zones of allied barbarian tribes. Whatever the defence strategy, it was apparently less successful in preventing barbarian incursions than in the 1st and 2nd centuries. This may have been due to heavier barbarian pressure, and/or to the practice of keeping large armies of the best troops in the interior, depriving the border forces of sufficient support. Byzantine army (641–1081) Komnenian Byzantine army (1081–1204) The Komnenian period marked a rebirth of the Byzantine army. At the beginning of the Komnenian period in 1081, the Byzantine Empire had been reduced to the smallest territorial extent. Surrounded by enemies, and financially ruined by a long period of civil war, the empire's prospects looked grim. At the beginning of the Komnenian period, the Byzantine army was reduced to a shadow of its former self: during the 11th century, decades of peace and neglect had reduced the old thematic forces, and the Battle of Manzikert in 1071 had destroyed the professional tagmata, the core of the Byzantine army. At Manzikert and later at Dyrrhachium, units tracing their lineage for centuries back to Late Roman army were wiped out, and the subsequent loss of Asia Minor deprived the Empire of its main recruiting ground. In the Balkans, at the same time, the Empire was exposed to invasions by the Norman Kingdom of Sicily, and by Pecheneg raids across the Danube. The Byzantine army's nadir was reached in 1091, when Alexios I Komnenos could manage to field only 500 soldiers from the Empire's professional forces. These formed the nucleus of the army, with the addition of the armed retainers of Alexios' relatives and the nobles enrolled in the army and the substantial aid of a large force of allied Cumans, which won the Battle of Levounion against the Pechenegs (Petcheneks or Patzinaks). Yet, through a combination of skill, determination and years of campaigning, Alexios, John and Manuel Komnenos managed to restore the power of the Byzantine Empire by constructing a new army from scratch. This process should not, however, at least in its earlier phases, be seen as a planned exercise in military restructuring. In particular, Alexios I was often reduced to reacting