Mars Ultor 'the Avenger'

At the battle of Philippi, Octavian vowed to avenge the assassination of Caesar. Mars is the Roman equivalent of Ares, the god of war in Greek mythology. Under Augustus, the worship of Mars gained a new prominance; not only was Mars the traditional guardian of the military affairs of the Roman state but, as Mars Ultor ('Mars the Avenger'), he became the personal guardian of the emperor in his role as avenger of Caesar.

Augustus, 27 BCE – 14 CE, Denarius minted around 18 BC.

Octavian set plans in motion to build a temple honoring Mars Ultor 'the Avenger'. While Rome had succeeded in conquering most of the civilized world, they had never succeeded against Parthia. The Parthian Empire was spread across Central Asia and posed a formidable challenge. Rome fought and lost to Parthia three times, the most devastating in 53 BCE. Crassus, the leader of the Roman army, was killed and Rome was humiliated, with the Roman standards of the Legions lost to the Parthians.

Carrhae was a horrible defeat for the Romans; Crassus was Rome’s richest man. The Parthians captured him and allegedly had him killed by pouring molten gold down his throat. The loss of a legion's standard the Aquilae (Eagle) was taken as a huge moral defeat.

Romans would spend decades fighting to recover them. Julius Caesar and Mark Antony both attempted to reclaim the Roman standards by force but failed due to heavy battlefield losses. After ascending the throne, Augustus wanted to reclaim them. Through conquering Armenia, he was able to secure a strong offensive position against the Parthians. The Parthian king felt threatened, and proposed a truce to Augustus, offering to return the Roman standards and any surviving prisoners of war. Augustus agreed and hailed the return of the Roman standards as a major victory against the Parthians. He used coinage to celebrate his triump. Although promised in 42 BCE, the temple’s construction only began in 20 BCE. The Temple of Mars Ultor was constructed in Augustus’ new forum and paid for using the spoils of war.

Objects inside the temple included the standards and Augustus’ chariot. (often shown with a legionary eagle.) Coins showing the Temple are sometimes labelled MAR VLT.

Silver denarius of Augustus, minted in Spain 19-18 BCE. The statue of Mars is also shown holding an aquila and the standards.