Why was the Roman Empire more powerful and versatile than the Greek Empire…?
Actually, there was one Greek empire which lasted longer than Rome. The Byzantine empire began in 312 ad. The languages used at the capital at first were Latin (rarely), and Greek. Justinian’s Code was the last major document the Byzantines published in two languages; after that, the pretense that it was a Latin empire ended, and all business was done in Greek. This Greek empire lasted until conquered by the Turks in 1453 ad., far outlasting the Roman empire. Even today, Greeks hang on to the ‘Great Idea’ of regaining Istanbul for the Greeks; which they claim has been ‘temporarily’ in foreign hands for the last 600 years.