 The Roman Empire succeeded the approximately 500-year-old Roman Republic ( 510 BC – 30 BC), which had been weakened by the conflict between Gaius Marius and Sulla and the civil war of Julius Caesar against Pompey and Marcus Brutus.During these struggles hundreds of senators were killed, and the Roman Senate had been refilled with loyalists of the First Triumvirate and later those of the Second Triumvirate.In 350 years, from the successful and deadliest war with the Phoenicians began in 218 BC to the rule of Emperor Hadrian by AD 117, Ancient Rome expanded up to twenty-five times its area.