Final answer:
Octavian, later known as Augustus, had no specific 'victory city' built in honor of his victory at the Battle of Actium; instead, his reign as emperor was marked by significant building projects in Rome.
Step-by-step explanation:
Octavian's decisive victory in the Battle of Actium, which took place in 31 BCE, was against the naval forces of Marc Antony and Cleopatra. Following this triumph, Octavian, who would later assume the title of Augustus and become the first Roman Emperor, built no specific 'victory city' to commemorate this particular event. However, his victory led to his complete control over Rome and began the transition from the Roman Republic to the Roman Empire. Augustus is renowned not for building a victory city, but for his extensive building projects throughout Rome, which included the construction of monumental structures such as the Forum of Augustus.