Arch of Septimius Severus

Stand at the foot of the arch and look up. The marble is pale and honey-grey, softened by eighteen centuries of rain. Around you, the ground of the Roman Forum is uneven, a patchwork of broken paving, weeds and old stone. Behind the arch, the slope of the Capitoline Hill rises steeply. In front of it, the long valley of the Forum opens out toward the Colosseum. On a warm afternoon you can hear footsteps on gravel, voices in many languages, and swifts screaming overhead.

This is the Arch of Septimius Severus. It was dedicated in the year 203, at the northwest end of the Forum, close to the old Senate House. It is a triumphal arch. That means it was built to celebrate a military victory and the man who led it. Here the victories were against the Parthians, a powerful empire that ruled the lands of present-day Iran and Iraq. Severus fought them in the 190s and returned to Rome as a conqueror.

Who was Septimius Severus? He was not born in Italy. He came from Leptis Magna, a wealthy Roman city on the coast of North Africa, in what is now Libya. He rose through the army and the Senate, and he seized power during a chaotic civil war in the 190s. He was a soldier first. He trusted the legions more than the Senate, and he made sure everyone in Rome could see what the legions had won for him.

Now look at the shape of the monument. It has three openings — a tall central passage and two smaller ones on each side. All three are linked by small inner passages, so the arch is almost hollow inside. The core is built of brick and travertine, a hard local limestone, and the whole surface is faced with marble. It rises more than twenty metres. Standing beneath it, you feel how it frames the sky and the Forum beyond.

The arch was not built for Severus alone. It also honoured his two sons, Caracalla and Geta. Severus wanted a dynasty. He wanted Rome to see a father and two heirs, united and strong. Ancient coins show that the top of the arch once carried a bronze chariot drawn by horses, with the emperor and his family riding on it. That bronze is long gone. Today the summit is flat and empty against the sky.

Here is the first surprise. Look closely at the large inscription across the top. The letters were once filled with gilded bronze. The bronze was stripped away long ago, but you can still see the cut-out letters and the small holes where the metal was fixed. And on the fourth line, something is wrong. The text was changed. A name was removed, and new words were carved in its place.

That missing name belongs to Geta. Severus died in Britain, at York, in 211. His two sons were supposed to rule together. They hated each other. Within months, Caracalla had his brother killed. According to the ancient historian Cassius Dio, Geta died in the arms of their mother, Julia Domna. Caracalla then ordered Geta's memory erased. Statues were destroyed, portraits were scraped, and his name was cut from monuments across the empire.

On this arch, Geta's name and titles were chiselled out. In their place, the carvers added a phrase in Latin that praises the emperors as the best and bravest of princes. It sounds like a compliment. In fact, it is a cover-up. If you know where to look, the fourth line looks slightly different from the lines above it. Scholars have studied the older bronze-fixing holes beneath the new letters, and these holes still carry traces of the original wording.

Now turn your attention to the four large relief panels above the side passages. They show scenes from the Parthian campaigns — soldiers, siege engines, cities under attack, and the emperor addressing his troops. The carving is crowded and busy, almost like a comic strip told in stone. Time and weather have worn many of the figures, so the scenes can be hard to read. Give your eyes a minute. Shapes of armour, walls and horses slowly appear.

Lower down, look at the bases of the columns. Each pedestal shows Roman soldiers leading Parthian prisoners. The captives wear trousers and soft caps, the clothing Romans used to mark people from the East. Their hands are often bound. These images were meant for the crowds walking past at eye level. Above the central passage, winged figures of Victory float in the corners, and smaller figures in the side passages represent river gods and the seasons.

Here is the second surprise. For much of the Middle Ages, this arch was partly buried. Centuries of earth, flood silt and rubble filled the Forum, and the ground rose several metres. Buildings were constructed against the arch, and a small church once stood beside it. The arch survived partly because people kept using it. Only with excavations in later centuries was the Forum floor cleared and the full height of the arch shown again.

Notice the setting around you. To one side stands the Senate House, a tall brick building with a plain front. Nearby are the remains of the Rostra, the speakers' platform where Roman politicians addressed the people. Behind you, the columns of the Temple of Saturn rise on their high base. Severus placed his arch right here on purpose. It sat at the political heart of the city, where everyone would pass under it or beside it.

The arch also connects to the Sacred Way, the old road that ran through the Forum. Triumphal processions moved along routes like this one, with soldiers, captives and treasures on display. Today, of course, there are no chariots. Visitors walk around the arch, not through it, because the passages are fenced off to protect the stone. Still, standing here, you are on the line where those parades once passed.

Before you move on, look once more at the fourth line of the inscription. Think of the brother who was erased, and the father who wanted his family remembered together forever. Then look at the worn soldiers on the column bases, still marching their prisoners after eighteen centuries. As you walk away toward the Forum, glance back. The arch stands quietly against the hill, holding its stories in stone, and keeping one secret in plain sight.