The Byzantine Military was the armed forces of the Byzantine Empire, which existed from the 4th to the 15th century. It evolved from the Roman military and was known for its strategic use of heavy cavalry, infantry, and naval forces. The military was organized into units called tagmata and themata, which allowed for effective regional defense and rapid response to threats. Byzantine soldiers were well-trained and often equipped with advanced weaponry for their time, including crossbows and catapults. The military also employed tactics such as Greek fire, a flammable liquid used in naval battles. The Byzantine military played a crucial role in defending the empire against various invasions and maintaining its territorial integrity.