Who is Belisarius of the Roman Empire from Strategy and what is their importance?

This general reconquered most of the Western Roman Empire, coming out of Constantinople while the Eastern region of the Roman Empire was still reasonably strong. This may have occurred simply because the West, which had been strong enough to shake off the Romans, had weakened, while the Eastern fringes had grown stronger in their resistance, hence changing the best direction for further expansion. Belisarius had a similar effect as Caesar upon those he conquered: some began to call him "the Emperor of the West".