Temple of Isis and Serapis

Stand still for a moment and feel the stones under your feet. These are smooth, dark cobbles, worn by centuries of shoes and cart wheels. Around you, ochre walls rise into narrow strips of sky. You may hear a scooter, a church bell, the clink of a café cup. What you will not see is a temple. And yet, somewhere beneath this pavement, one of the strangest sanctuaries of ancient Rome once stood.

This was the sanctuary of Isis and Serapis, two gods who came to Rome from Egypt. Scholars often call it the Iseum Campense, because it stood in the Campus Martius. That was the low, flat plain inside the bend of the Tiber, once used for military drills and later filled with temples, baths and theatres. Today the same ground holds the Pantheon, the church of Santa Maria sopra Minerva, and a maze of quiet lanes.

Who were these gods? Isis was an Egyptian mother goddess, a protector of sailors, of families, and of the dead. Serapis was a god shaped in Hellenistic Egypt, a blend of Greek and Egyptian ideas. He was usually shown with a full beard and a basket of grain on his head. Together they promised something many Romans wanted — a personal bond with a caring god, and hope beyond death.

Rome did not welcome them easily. The official religion valued order and old Roman custom. Foreign cults with night rituals, shaved priests and secret rites made the Senate nervous. Ancient writers describe several moments when shrines to Isis were torn down by order of the state. And still the worship returned, again and again. Sailors, merchants, freed slaves and wealthy women kept the goddess alive in the city.

One ancient story shows how tense this was. The Jewish historian Josephus tells of a scandal under the emperor Tiberius. In his account, a Roman noblewoman was tricked inside the temple by a man pretending to be a god. When the deception came out, Tiberius punished the priests and ordered the sanctuary destroyed. Historians debate how much of the tale is accurate. But it tells us how Romans saw this place — exotic, powerful, and a little dangerous.

Then the mood changed. Later emperors embraced the Egyptian gods. Josephus also records that Vespasian and his son Titus spent a night at the sanctuary of Isis before their great triumph over Judaea. After a fire swept through the Campus Martius in the year 80, the emperor Domitian rebuilt the complex on a grand scale. Later rulers restored it again. For a time, this was one of the richest religious sites in the capital.

How do we know what it looked like? Partly from the Severan Marble Plan, a huge map of Rome carved in stone in the early third century. Only fragments survive, but some of them show this sanctuary. They suggest a long precinct with courtyards, porticoes and a curved hall at one end. Picture a garden of Egypt in the middle of Rome — palms, pools, obelisks, and statues of sphinxes and sacred animals.

Here is the first surprise. The temple is gone, but pieces of it are still all around you. Walk a few steps to Piazza della Minerva and look at the little marble elephant. On its back stands a small Egyptian obelisk. That obelisk was found in this area in the seventeenth century, and it most likely came from the sanctuary of Isis. Gian Lorenzo Bernini designed the monument, and his workshop carved the elephant.

Now turn toward the Pantheon. The obelisk in the fountain of Piazza della Rotonda is also believed to come from the same complex. Other obelisks from this sanctuary travelled much farther — one stands near Termini station, and others ended up in Florence and Urbino. The ancient Romans shipped these stones from Egypt as trophies and sacred objects. Centuries later, popes and princes moved them again.

The second surprise is even stranger. Look for a narrow street called Via del Piè di Marmo — the street of the marble foot. There, on the pavement, rests a giant sandalled foot carved from white marble. Many scholars think it belonged to a colossal statue from the sanctuary. Nearby, on a cornice high above Via della Gatta, sits a small stone cat. Locals say it came from the temple too, where cats were sacred to the Egyptians.

The pieces keep appearing. A colossal female bust stands near the church of San Marco, close to Piazza Venezia. Romans call her Madama Lucrezia, and she may show Isis or one of her priestesses. Two great reclining river gods, the Nile and the Tiber, were dug up near Santa Maria sopra Minerva in the early sixteenth century. Today the Nile sits in the Vatican Museums, and the Tiber in the Louvre in Paris.

Even the church names carry traces. The nearby church of Santo Stefano del Cacco takes its odd name from a statue of a baboon, an animal linked to the Egyptian god Thoth. According to the usual explanation, Romans called the statue a macaco, a monkey, and the word shortened over time. So a small Roman church still carries the memory of an Egyptian animal god in its name.

Why did the sanctuary vanish so completely? As Christianity became the religion of the empire, pagan temples lost their funding and their purpose. Stone was reused, buried, or burned for lime. Medieval houses grew over the foundations. The ground level of this district rose by several metres. What survived was scattered — a foot here, an obelisk there, a cat on a roof.

So take one more look around you. The Gothic church, the café tables, the shuttered windows... all of it sits on top of a garden that once belonged to Egyptian gods. As you walk away, keep your eyes a little higher, and a little lower, than usual. On a cornice, at a corner, in a fountain, a piece of that lost sanctuary may still be watching you pass.