<P> 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 . </P>
<P> 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 . </P>
what was the power structure of the byzantine empire
what was the power structure of the byzantine empire
Byzantine army
Byzantine army