The Battle of Actium, which took place off the Greek coast in 31 B.C. was a decisive naval battle between two great generals and rivals of the Roman Republic: Mark Antony and Octavius Caesar, also known as Octavian. The two had originally been allies who had formed the second ruling Roman triumvirate (along with the more minor figure of Lepidus) after the assassination of Octavian's grand-uncle, Julius Caesar; however, in the power vacuum left by Caesar's assassination, a fierce struggle for supremacy ensued between these two strong, ambitious men.
The battle of Actium saw Octavian crush Antony's forces and those of Antony's Egyptian ally and lover, Cleopatra, ultimately leading to both their suicides, and ensuring that Octavian was left the single most powerful figure in all of the Roman world (he also annexed Egypt as a Roman province).The battle of Actium, when he gained his first really decisive blow against his great rival, is generally regarded as the true beginning of the end of the Roman Republic and the first step towards the establishment of the Roman empire in its stead. Octavian gradually consolidated his personal hold on Rome and its dominions and eventually went on to become the first Roman emperor under the title of Caesar Augustus, greatly expanding Rome's sphere of influence over Europe.
Therefore the significance of the Battle of Actium can hardly be overstated, as its ultimate result was the formation of the Roman empire, which would last for hundreds of years and profoundly affect the development of European languages and civilization as a whole. The influence of the Roman empire has proved exceptionally long-lasting, and the long-ago Battle of Actium was instrumental in its very beginnings.