Together with Mark Antony and Marcus Lepidus, he formed the Second Triumvirate to defeat the assassins of Caesar.

That occurred when Mark Antony, the other most influential member of the Triumvirate, abandoned his wife, Octavian's sister Octavia Minor, and moved to Egypt to start a long-term romance with Cleopatra, thus becoming de facto stepfather to Caesarion.

After years of loyal cooperation with Octavian, Mark Antony started to act independently, eventually raising the suspicion that he was vying to become the sole master of Rome.

Octavian complained that Antony had no authority for being in Egypt ; that his execution of Sextus Pompeius was illegal ; that his treachery to the king of Armenia disgraced the Roman name ; that he had not sent half the proceeds of the spoils to Rome according to his agreement ; that his connection with Cleopatra and the acknowledgment of Caesarion as a legitimate son of Julius Caesar were a degradation of his office and a menace to himself.

During 32 BC, a third of the Senate and both consuls allied with Antony.

Octavian was not present, but at the next meeting made a reply of such a nature that the consuls both left Rome to join Antony ; and Antony, when he heard of it, after publicly divorcing Octavia, came at once to Ephesus with Cleopatra, where a vast fleet was gathered from all parts of the East, of which Cleopatra furnished a large proportion.

After staying a time with his allies at Samos, Antony removed to Athens.

After Octavian's proposals for a conference with Antony had been scornfully rejected, both sides prepared for the final struggle next year.

Mark Antony and Gellius Publicola commanded the right wing of the Antonian fleet, while Marcus Octavius and Marcus Insteius commanded the centre, with Cleopatra's squadron positioned behind them.

Mark Antony transferred to a smaller vessel with his flag and managed to escape, taking a few ships with him as an escort to help break through Octavian's lines.

Antony seized the opportunity and with Cleopatra on her ship and him on a different ship, sped through the gap and escaped, abandoning his entire force.

Antony, who had found himself generally deserted, after vainly attempting to secure the army stationed near Paraetonium under Pinarius, and sending his eldest son Antyllus with money to Octavian and an offer to live at Athens as a private citizen, found himself in the spring attacked on two sides.

In Rome, Caesar was appointed dictator, with Mark Antony as his Master of the Horse ( second in command ); Caesar presided over his own election to a second consulship and then, after eleven days, resigned this dictatorship.

He was granted a golden chair in the Senate, was allowed to wear triumphal dress whenever he chose, and was offered a form of semi-official or popular cult, with Mark Antony as his high priest.

It had been literally degraded since the 1st century, when in 44 BC the consul Mark Antony did not scruple to run with the Luperci ; now the upper classes left the festivities to the rabble.

He first appears in history in 40 BC, when he was employed by Octavian in arranging his marriage with Scribonia, and afterwards in assisting to negotiate the treaty of Brundisium and the reconciliation with Mark Antony.

To his influence especially was attributed the more humane policy of Octavian after his first alliance with Antony and Lepidus.

After Caesar's assassination, Antony formed an official political alliance with Octavian ( the future Augustus ) and Lepidus, known to historians today as the Second Triumvirate.

Antony exercised his tribunician veto, with the aim of preventing a senatorial decree declaring martial law against the veto, and was violently expelled from the senate with another Caesar adherent, Cassius, who was also a tribune of the plebs.

Caesar was most displeased with the whole affair and removed Antony from all political responsibilities.

The estrangement was not of long continuance, with Antony meeting the dictator at Narbo ( 45 BC ) and rejecting the suggestion of Trebonius that he should join in the conspiracy that was already afoot.

Struck in 41 BC, this coin was issued to celebrate the establishment of the Second Triumvirate by Octavian, Antony and Marcus Aemilius Lepidus ( triumvir ) | Marcus Lepidus in 43 BC.

* 43 BC – The Second Triumvirate alliance of Gaius Julius Caesar Octavianus (" Octavian ", later " Caesar Augustus "), Marcus Aemilius Lepidus, and Mark Antony is formed.

The Second Triumvirate is the name historians give to the official political alliance of Octavian ( later known as Augustus ), Marcus Aemilius Lepidus, and Mark Antony, formed on 26 November 43 BC with the enactment of the Lex Titia, the adoption of which marked the end of the Roman Republic.

One of the first examples of rule by decree was in the ancient Roman Republic when, after the assassination of Julius Caesar in 44 BC, his successor, Gaius Octavian, general Mark Antony and succeeding pontifex maximus Aemilius Lepidus seized power in the Second Triumvirate, officially recognized by the senate by the Lex Titia decree.

A Lex Titia formalized the rule of Octavian, Mark Antony, and Marcus Aemilius Lepidus.

Antony formed the second triumvirate with Octavian ( the future emperor Augustus ) and Marcus Aemilius Lepidus on 43 BC and began to conduct proscriptions.

After Caesar's murder, Antony pursued Caesar's assassins and vied for supreme power with Octavian ( later to become Caesar Augustus ), first forming an alliance with Octavian ( and Marcus Aemilius Lepidus ) in the Second Triumvirate, then being defeated by him at the Battle of Actium in 31 BC.

Prior to the establishment of the Empire, the territories of the Roman Republic had been divided among the members of the Second Triumvirate: Mark Antony, Octavian and Marcus Aemilius Lepidus.

But the following year he turned to Mark Antony, and he held the consulship with Marcus Aemilius Lepidus in 42 BC.

Pedius was left in charge of Rome, while his colleague and cousin left for Northern Italy to join Mark Antony and Marcus Aemilius Lepidus, in forming the Second Triumvirate.

The Lex Titia was a Roman law passed on November 27, 43 BC, that legalized the Second Triumvirate of Octavian, Marc Antony, and Marcus Aemilius Lepidus.

The Triumvirate was eventually torn apart under the competing ambitions of its members: Lepidus was driven into exile and stripped of his position, and Antony committed suicide following his defeat at the Battle of Actium by Augustus in 31 BC.

Antony complained that Octavian had exceeded his powers in deposing Lepidus, in taking over the countries held by Sextus Pompeius, in enlisting soldiers for himself without sending half to him.

When they knew that Marcus Junius Brutus and Gaius Cassius were assembling an army in order to march on Rome, Antony, Octavian and Lepidus allied in November 43 BC, forming the Second Triumvirate to stop Caesar's assassins.

* November 26 – Octavian meets Antony and Lepidus in Bononia, and the three enter into an official five-year autocratic pact, the Second Triumvirate.

* Octavius, Mark Antony, Lepidus: Triumvirs after the death of Julius Caesar

* Mark Antony, Gaius Julius Caesar Octavianus and Marcus Lepidus sign the Treaty of Tarentum ( or 37 BC ), extending the Second Triumvirate until 33 BC.

Cleopatra by John William Waterhouse ( 1888 ) Mark Antony – one of the Triumvirs of Rome along with Octavian and Lepidus – has neglected his soldierly duties after being beguiled by Egypt's Queen, Cleopatra.

Roman aureus | aurei bearing the portraits of Mark Antony ( left ) and Octavian ( right ), issued in 41 BC to celebrate the establishment of the Second Triumvirate by Octavian, Antony and Marcus Lepidus in 43 BC.

He had been warring with Antony and Lepidus in upper Italia.

As had been the case with both Sulla and Julius Caesar during their dictatorships, the members of the Triumvirate saw no contradiction between holding a supraconsular office and the consulate itself simultaneously ( Lepidus was consul in 42 BC, Antony in 34 BC, and Octavian in 33 BC ).

Octavian — who had begun calling himself " Divi filius " (" son of the divinity ") after Caesar's deification as Divus Iulius (" the Divine Julius ") and now styled himself simply " Imperator Caesar " — took control of the West, Antony of the East, and Lepidus of Hispania and Africa.

Antony detested Octavian and spent most of his time in the East, while Lepidus favoured Antony but felt himself obscured by both his colleagues, despite having succeeded Caesar as Pontifex Maximus in 43 BC.

With the complete defeat of Antony and the marginalisation of Lepidus, Octavian, having restyled himself " Augustus " in 27 BC, remained as the sole master of the Roman world, and proceeded to establish the Principate as the first Roman " emperor ".

In Rome the three main Caesarian leaders ( Antony, Octavian and Lepidus ), who controlled almost all the Roman army in the west, had crushed the opposition of the senate and established the second triumvirate.

The triumvirs decided to leave Lepidus in Italy, while the two main partners of the triumvirate ( Antony and Octavian ) moved to Northern Greece with their best troops ( a total of 28 legions ).