Eastern Roman Empire after Roman Empire collapsed , they was known for there war against Persian Sassanid Empire in Levant and Mesopotamia, and the Famous plague of Justinian, in their period there was the worst year in the history (536) which killed alot of people by starvation and cold ,and they’re known for their fire which you couldn’t extinguish it, Greek fire, the most powerful weapon against ships and infantry, also they known for their holy wars with Muslims which finally Ottomans conquered it.
the most interesting thing also is Constantinople ,Constantinople was famed for its massive and complex defences. The Theodosian Walls consisted of a double wall lying about 2 kilometres (1.2 mi) to the west of the first wall and a moat with palisades in front.
This formidable complex of defences was one of the most sophisticated of Antiquity. The city was built intentionally to rival Rome, and it was claimed that several elevations within its walls matched the ‘seven hills’ of Rome. Because it was located between the Golden Horn and the Sea of Marmara the land area that needed defensive walls was reduced, and this helped it to present an impregnable fortress enclosing magnificent palaces, domes, and towers, the result of the prosperity it achieved from being the gateway between two continents (Europe and Asia) and two seas (the Mediterranean and the Black Sea). Although besieged on numerous occasions by various armies, the defences of Constantinople proved impregnable for nearly nine hundred years, also they known for their interesting mosaic art and architectural art which it’s one of great arts in the history of human.
finally they known for fourth crusade of Papacy state which was the first fall of Constantinople .
thank you for reading