The Romans liked to erect monuments commemorating military victories or other achievements. There was a long tradition in Roman society of immortalizing these actions in stone. As time went on, the physical city itself began more and more to symbolize Rome's conquest of the Mediterranean world through its actual structures. The city itself could be considered a giant trophy case for the display of captured objects, since its public spaces were decorated with items stolen from all over the Mediterranean during Roman campaigns. Temples such as those of Mars the Avenger and Jupiter Optimus Maximus were literally stuffed to overflowing with captured enemy flags, standards, armor, and other military trophies. The streets, gardens, baths, and houses of Rome were decorated with works of art seized during Rome's campaigns, particularly in the Greek East. Finally, the very stones that made up the great public buildings of Rome were themselves reminders of Rome's status as conqueror of the known world. Rome imported colored marbles and decorative stones at great expense and effort from all over the Mediterranean. Thus, many of the buildings that made up the city were themselves composed of booty from the conquered territories, and anyone walking around the city of Rome would have been constantly confronted with highly visible reminders of Rome's dominance over the Mediterranean.
One common form of victory monument that the Romans built was the triumphal or commemorative arch. These probably had their origins in temporary decorations that were placed on archways through which generals passed when celebrating a special ritual known as a triumph. A triumph was essentially a parade granted to a victorious general. The day would be declared a public holiday, and the general, his troops, prisoners of war, and captured booty would march through the streets of the city while the people gathered to cheer them. Triumphs were not given to all generals but rather were awarded by the senate as a special honor. In order for a general to qualify for a triumph, at least 5,000 enemy troops had to have been killed during his campaign. Between 220 and 70 bc, 100 triumphs were granted. During the empire, triumphs were limited to the emperor and members of his family.
The procession would assemble outside Rome in the Campus Martius and then enter the city through a gate known as the Porta Triumpbalis. The route wound through the city, passing by the Circus Maximus, around the Palatine, and along the Via Sacra, and ending up at the foot of the Capitoline hill. It culminated with the triumphator climbing up the Capitoline to the Temple of Jupiter Optimus Maximus, where a sacrifice was performed. The triumphator was dressed in the toga picta, which was purple with gold trim, and his face was painted red so that he looked like the cult statue of Jupiter on the Capitoline, He rode in a gilded four-horse chariot accompanied by a slave who held a gold crown over his head and whispered in his ear that fortune was fleeting. His troops accompanied him, shouting the acclamation "lo Trhimphe."
An idea of what a triumph was like can be gained by considering the one celebrated by a general named Lucius Aemilius Paullus, who conquered Macedon during the republic. This was by no means the most spectacular triumph ever staged, but it nevertheless took three entire days. On the first day, 250 wagons loaded with all the artworks that Lucius Aemilius Paullus had stolen while in Greece rolled through the streets. On the second day, the crowds witnessed wagons burdened with the weapons and armor of all the foreigners that his army had killed, followed by wagons carrying 2,250 talents of silver. The third and final day began with a parade of 231 talents of gold, followed by the golden plates and tableware of the defeated enemy king, then the golden crown of the enemy king, then members of the enemy king's immediate family, then the enemy king in chains marching before a golden chariot, in which stood Lucius Aemilius Paullus himself, wrapped in a purple toga.