Final answer:
Roman triumphal arches served to memorialize military victories, honor leaders, and symbolize the empire's power. They featured historical reliefs for propaganda purposes and were central elements in victory processions. These arches were as much about aesthetics as they were about commemorating historical events.
Step-by-step explanation:
The chief functions of the Roman triumphal arch were to commemorate significant victories in battle, honor emperors or military leaders, and serve as a monumental and decorative symbol of Roman power and achievements. Not merely a gateway, these arches functioned symbolically to represent military triumphs and the strength of the empire. They often depicted various historical reliefs chronicling the victory being celebrated and were part of imperial propaganda imagery. For example, the Arch of Septimius Severus celebrated his victories over the Parthians and symbolized the continuity of his imperial rule, while the Arch of Titus commemorated Titus's victories, including the siege of Jerusalem, and these arches provided a backdrop for processions. Remarkably, several of these testaments to Rome's grandeur, such as the Arch of Constantine, which proclaimed his victory over Maxentius and symbolized a peaceful era, still stand today.
In essence, Roman triumphal arches stood as grand architectural and sculptural fusions that provided an ornamental demonstration of Rome's glory and the accomplishments of its leaders, rather than performing a specific functional purpose. They were strategically placed along processional routes and close to significant landmarks, like the Forum and the Capitolium, enhancing the cityscape and reinforcing the might of the empire both to its citizens and to foreign dignitaries.