The Roman Emperor was the ruler of the Roman State during the imperial period (starting at about 27 BC). The Romans had no single term for the office: Latin titles such as imperator (from which English emperor ultimately derives), augustus, caesar and princeps were all associated with it. In practice, the Emperor was supreme ruler of Rome and supreme commander of the Roman legions. In theory, however, Rome remained a republic, the res publica, and the Emperor's status was merely that of primus inter pares—first among equals. This legal fiction became increasingly meaningless as the Emperors consolidated their power. However, it was maintained at least to a ceremonial degree until the very end of the Roman Empire. The Western Roman Empire met its end in 476 and the Eastern Roman Empire in 1453.