Final answer:
Octavian's triumph over Marc Antony culminated at the Battle of Actium in 31 BCE and was followed by his ultimate rise to power as Augustus in 27 BCE, signifying a prolonged metaphorical 'triumph' rather than a single celebratory event.
Step-by-step explanation:
The triumph of Octavian, who later became known as Augustus, marked the end of the civil wars and the inception of the Roman Empire. His victory over Marc Antony at the Battle of Actium in 31 BCE, followed by the consolidation of power and the declaration as Augustus in 27 BCE, were key moments in this transition.
The triumph itself, as a ceremonial event, does not have a specific recorded duration, but the transition from Republic to Principate under Octavian's authority represents his metaphorical and prolonged 'triumph' over the old systems of power.
While it is clear that Octavian's grip on power and the establishment of the Empire was a process that occurred over several years, the actual celebratory triumphs that Roman generals would partake in after a victory were typically singular events that lasted for a day. However, in the case of Octavian (Augustus), because the specific duration of his celebratory triumph is not well-documented, we focus more on the symbolic and partial transformation of the Roman state from a Republic to an Empire as his lasting 'triumph.'