Eastern Roman army

The Eastern Roman army was the military force of the eastern part of the Roman Empire. It existed from the time the empire split in 395 AD until changes happened after losing important lands in the 7th century. This army grew out of the later versions of the Roman army and slowly changed over time.

At first, the Eastern Roman army was very similar to the armies of both the eastern and western parts of the Roman Empire. Over time, especially between the 5th and 7th centuries, it changed a lot. Cavalry became more important, and mobile armies started playing bigger roles.

In the 6th century, Emperor Justinian I sent many soldiers to try to take back parts of the old Western Roman Empire. They succeeded in taking back areas in North Africa, most of Italy, and parts of southern Spain. However, the strength of the army dropped because of a big disease called the Plague of Justinian. Later, in the 7th century, the army fought hard against the Sasanian Empire under Heraclius. Although they won back Egypt and Syria for a short time, they soon had to face new enemies from the Rashidun Caliphate. Losses in battles like the Battle of Yarmuk led to big changes in how the army was organized.