The Basilica of Saints Cosmas and Damian (Santi Cosma e Damiano)

In the area of the Imperial Forums, occupying a former building, the Basilica of Saints Cosmas and Damian (Santi Cosma e Damiano) is an example of the conversion of a pagan structure into a church.

As well as being a haven of peace during a visit to this area, it has a remarkable mosaic in its apse and other curiosities.

Getting there : Colosseo metro station or by bus to Piazza Venezia, lines 51, 60, 63, 80, 83…

Address : 1 via dei Fori Imperiali

Opening hours : Every day from 10:00 to 13:00 and from 15:00 to 18:00.

Ticket prices: free admission; donation for the crypt.

The Ostrogothic emperor Theodoric the Great, although an Arian, offered Pope Felix IV two buildings in which to construct a church. They were one of the two libraries of Vespasian's Forum of Peace and the Temple of Romulus, dedicated to the son of the emperor Maxentius, who died at the age of five.

Pope Felix IV therefore erected in 526 a single-nave church and in 530 adorned the apse with a mosaic in honour of the physician saints Cosmas and Damian.

In the 7th century Pope Sergius V added an upper register on a gold ground to the mosaic.

In 1632 Pope Urban VIII ordered the remodelling of the church, which had been invaded by silt, raising it by 7 metres. He added side chapels and a convent with its cloister.

Since 1947 and the restoration of the Temple of Romulus, the entrance is no longer from the Forum but from the Via dei Fori Imperiali.

After passing through the entrance porch, you arrive at the small Renaissance cloister with, at its centre, a fountain reconstructed from antique elements.

As soon as you enter the church, look at the coffered ceiling which bears the Barberini bees and the frescoes of the side chapels illustrating the life of the physician saints.

A 17th-century Baroque altar partly conceals the apse mosaic, but the eye and attention are irresistibly drawn to the apse and its magnificent 7th-century mosaic.

From bottom to top you will first see twelve sheep, the twelve apostles, moving towards the Lamb of God, Christ, set on a mound from which spring the four rivers of paradise, identified with the four Gospels. The scene is framed by two palm trees, symbols of Paradise, and a phoenix, that of the Resurrection.

Above, St Peter and St Paul, dressed in white, present Saints Cosmas and Damian to Christ. St Peter, with white hair and beard, presents St Cosmas bearing the crown of martyrs but with his hands covered as a sign of respect and humility. He is followed by St Theodore in the costume of a high official of the Byzantine court.

On the other side it is St Paul, with brown hair because he was younger in his preaching, who with his hand stretched towards Christ presents St Damian. He is followed by Pope Felix IV carrying the model of the church whose construction he ordered. The two saints are very alike apart from their costumes, because they were twin brothers.

Apart from Christ, no one is haloed; that iconographic tradition came later. In the centre, Christ emerging from pastel clouds points with one hand to a star, symbol of the Paradise that awaits the martyrs, and with the other holds out the scroll of the Law. Behind the saints flows the Jordan, symbol of the Baptism necessary to receive Divine Grace. The triumphal arch has a gold ground, unlike the blue of the apse. Angels float on blue and red clouds because they are already in the glory of Christ, as are the Evangelists, including the eagle of St John carrying his Gospel and the winged man of St Matthew; as a result of the 17th-century works, St Mark and St Luke have disappeared.

Take all the time you need to examine and appreciate the fine execution of this mosaic, for example the halo of Christ formed of a multitude of gold tesserae with an outer circle of very pale blue standing out against the darker blue of the sky.

Before leaving, glance through a window at the interior of the Temple of Romulus below. To see the former entrance and its antique bronze door, you will need to go into the Roman Forum.

If the convent door is open you can see in a room an impressive Neapolitan nativity scene.