Though the Battle of Cynocephalae in 197 BCE is often cited as the birth of the Roman Empire, the equally famous Battle of Actium is a better candidate.With the overthrow of the last Roman king, the Roman Republic was ruled by a senate and assembly from 509 BCE until Julius Caesar's appointment as Dictator in 44 BCE. The battle of Cynocephalae in 197 BCE consolidated Rome's power in the Mediterranean but did not launch the Roman Empire - that came about, at least in part, due to the dynamics in the relationships of three very strong personalities, Octavian, Mark Antony and Cleopatra, and a tragic love affair between two of them.
Born Gaius Octavius Thurinus, Octavian was adopted by his great uncle Julius Caesar in 44 BCE and was afterwards known as Gaius Julius Caesar Octavianus. When Julius Caesar was assassinated 15 March 44 BCE, Octavian was named as heir in his will and came to Rome where he allied himself with Mark Antony and Marcus Aemilius Lepidus to hunt down and punish the assassins. Forming themselves into the Second Triumvirate, the three would work well together (at least on the surface of things) until the assassins Brutus and Cassius were defeated in October of 42 BCE at the Battle of Philipi. Lepidus was given Africa to govern (which effectively removed him from any further power plays) while Antony took the east and headed to Egypt and Octavian governed in Rome.
Julius Caesar's third cousin, once removed, Marcus Antonius was a brilliant General, much loved by his soldiers, and Caesar's best friend. As renowned as he was as a leader of men, he was equally known for his inordinate love of pleasure in the form of wine, women and gaming. In Egypt he found the perfect companion for these pursuits in Cleopatra VII. Plutarch tells us, "Plato admits four sorts of flattery, but she had a thousand...she played at dice with him, drank with him, hunted with him...at night she would go rambling with him to disturb and torment people at their doors and windows, dressed like a servant woman" (Lives). In a short time, Antony fell in love with Cleopatra and she with him.
Cleopatra VII Philopator had a son, Caesarion, by Julius Caesar, and had actually met Antony years before when she was a young girl. Much to the dismay of Octavian and the general Roman public, Antony would have three children with Cleopatra (though he was now married to Octavian's sister, Octavia Minor, since 40 BCE) and would acknowledge them publicly. In 33 BCE Antony divorced Octavia and, in a letter to Octavian, wrote, "What's upset you? Because I go to bed with Cleopatra?...Does it really matter where, or with what women, you get your excitement?" (Ancient Rome). Antony then claimed that Caesarion, not Octavian, was the true legitimate heir to Julius Caesar, calling Caesarion the "King of Kings". Octavian, who had long resented Antony, was outraged at this and persuaded the Senate to declare war on Cleopatra knowing, naturally, that Antony would be drawn into battle.
On the morning of 2 September 31 BCE the fleets of Mark Antony and Cleopatra met the fleet of Octavian outside the Gulf of Actium in Greece. Antony's ships were large quinqueremes which were built primarily for ramming and sinking opponent's vessels. His ships, however, were seriously undermanned due to a malaria outbreak which had struck his crews. Octavian's ships, on the other hand, were smaller and fully manned with healthy crews. A further blow against Antony's hopes for success was the defection of one of his Generals, Quintus Dellius, to Octavian's side with all of Antony's battle plans. Octavian drew Antony's fleet out and, sometime after mid-day, Antony engaged his enemy. It was apparent, shortly, that the battle was not going well for Antony. Cleopatra, with her sixty ships, raised sail and left the battle for the open ocean. Antony immediately left his command ship and followed Cleopatra with forty of his own ships, leaving some 5,000 men and 300 ships to be destroyed by Octavian. Why Cleopatra, then Antony, left the battle has always been a matter of conjecture and speculation. Some say Antony lost his nerve when he saw Cleopatra leaving the fight while others claim their action was a pre-planned escape should the battle go toward Octavian's side. Whatever the reason was, the result was complete victory for Octavian. Defeat followed on defeat for Antony and, the following August, he committed suicide by stabbing himself, dying in Cleopatra's arms, and she, then, allowed herself to be bitten by a poisonous asp preferring death to humiliation by Octavian. Later that year Octavian had Caesarion murdered by strangulation (stating that “two Caesars are one too many”) and ordered the execution of Antony’s oldest son, whom he considered the only threat. Octavian then was the supreme ruler of Rome and her provinces and, in 27 BCE, was given the title `Augustus’ (Illustrious One) by the Roman Senate, becoming Augustus Caesar, first emperor of Rome; and so the Roman Empire was born.