Byzantine military

Byzantine Army
Participant in wars of the Byzantine Empire
Active	c. 660–1453
Leaders	Roman Emperor (Commander-in-chief)
Headquarters	Constantinople
Area of operations	Balkans, Asia Minor, Middle East, Italy, North Africa, Spania, Caucasus, Crimea
Part of	Byzantine Empire
Originated as	Late Roman army
Allies	Huns, Lombards, Bulgars, Crusader states, Anatolian beyliks, Khazars, Axum, Avars, Rus', Magyars, Heruli
Opponents	Goths, Huns, Sassanid Persia, Vandals, Ostrogoths, Avars, Slavs, Muslim Caliphate, Bulgaria, Rus', Normans, Crusader states, Seljuks, Anatolian beyliks, Ottomans and others

This article is part of the series on the military of the Byzantine Empire, 330–1453 AD
Structural history
Byzantine army: East Roman army, Middle Byzantine army (themes • tagmata • Hetaireia), Komnenian-era army (pronoia), Palaiologan-era army (allagia) • Varangian Guard • Generals (Magister militum • Domestic of the Schools • Grand Domestic • Stratopedarches • Protostrator)
Byzantine navy: Greek fire • Dromon • Admirals (Droungarios of the Fleet • Megas doux)
Campaign history
Lists of wars, revolts and civil wars, and battles
Strategy and tactics
Tactics • Siege warfare • Military manuals • Fortifications (Walls of Constantinople)
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The Byzantine army or Eastern Roman army was the primary military body of the Byzantine armed forces, serving alongside the Byzantine navy. A direct descendant of the Roman army, the Byzantine army maintained a similar level of discipline, strategic prowess and organization. It was among the most effective armies of western Eurasia for much of the Middle Ages. Over time the cavalry arm became more prominent in the Byzantine army as the legion system disappeared in the early 7th century. Later reforms reflected some Germanic and Asian influences – rival forces frequently became sources of mercenary units e.g.; Huns, Cumans, Alans and (following the Battle of Manzikert) Turks, meeting the Empire's demand for light cavalry mercenaries. Since much of the Byzantine military focused on the strategy and skill of generals utilizing militia troops, heavy infantry were recruited from Frankish and later Varangian mercenaries.

From the seventh to the 12th centuries, the Byzantine army was among the most powerful and effective military forces in the world – neither Middle Ages Europe nor (following its early successes) the fracturing Caliphate could match the strategies and the efficiency of the Byzantine army. Restricted to a largely defensive role in the 7th to mid-9th centuries, the Byzantines developed the theme-system to counter the more powerful Caliphate. From the mid-9th century, however, they gradually went on the offensive, culminating in the great conquests of the 10th century under a series of soldier-emperors such as Nikephoros II Phokas, John Tzimiskes and Basil II. The army they led was less reliant on the militia of the themes; it was by now a largely professional force, with a strong and well-drilled infantry at its core and augmented by a revived heavy cavalry arm. With one of the most powerful economies in the world at the time, the Empire had the resources to put to the field a powerful host when needed, in order to reclaim its long-lost territories.

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Wikipedia