If I could travel in time there are umpteen periods I’d love to visit. If I could only choose one, I think I’d go for the mid 1400s. The quattrocento has always struck me as an exciting period, an intermingling of strife and elegance. And there were some splendid hats. One of them was worn by Cardinal Bessarion, an intriguing figure of extraordinary erudition. He is often credited with the reunion – albeit not definitive – of the Eastern and Roman Churches in 1439 after four centuries of schism. His efforts were recognised and he was created Cardinal in the Roman Church. Bessarion remained in Italy for the rest of his life, directing his, ultimately thwarted, attempts to save Constantinople from falling to the Turks from his Palace attached to the Basilica of the Twelve Apostles, just off the modern Piazza Venezia. This was the church of which he was titular cardinal, and where he commissioned and oversaw restoration and decoration, including his own funerary chapel.

Cardinal Bessarion, 1403 – 1472

I had been meaning to visit the chapel since it opened to the public two or three years ago following an interminable restoration project, but it had rather odd opening hours and I didn’t get round to it. Then, a couple of weeks ago, I found myself in the area on a bright wintry day and decided to drop into the church and have a look around. The chapel’s odd opening hours appear, happily, to have become less odd. A world away from the bright blue sky outside, the gloomy shadows of the chilly and deserted church revealed a lady in late middle age half way along the right nave. Wrapped in multiple layers against the cold, and sitting by an open side door which gave access to the chapel, she confessed that she had been contemplating going home early and that nobody had been in all morning.

If I’m honest I had absolutely no idea what to expect, my vague enthusiasm had never led to a more concrete investigation of what, or where exactly, the Bessarion Chapel actually was. I’d imagined a separate room I suppose. In fact the doorway led me into a high, tight space behind the eighteenth-century side chapel of the Odescalchi family. The Bessarion chapel had fallen victim to a series of vicissitudes since decoration was completed in 1468. Damaged by the flooding of the Tiber, and by the sack of the city in 1527, it was then all but swept away by subsequent remodellings, most recently the building of the Odescalchi Chapel between 1719 and 1723. Shallower than the Bessarion Chapel, the new space effectively bricked in the former. Referred to in various seventeenth century descriptions, its existence was only verified in 1959 during maintenance work on the basilica side of the Palazzo Colonna.

I loved the “hidden” nature of the space. I’ve always been very fond of handing over a couple of euros in unlikely corners of churches and climbing rickety staircases or being ushered into improbable elevators. Discovering frescoes and mosaics in long bricked-in corners of organ lofts and forgotten chapels fills me with joy, and this was another to add to my list. The better preserved section of the frescoes is the upper register. To view these one climbs a metal staircase, reaching a steel platform of somewhat alarming mobility.

The chapel’s original dedication was to the Virgin, and Saints John the Baptist, Michael, and Eugenia, and the fresco decoration was commisssioned from Antoniazzo Romano, with the assistance of Melozzo da Forlì, making it one of the most important pictorial projects in fifteenth century Rome (other fragments of the decoration of the church’s main apse carried out at the same time can today be seen in the Vatican Museums and the Palazzo del Quirinale). Descriptions which pre-date the building of the Odescalchi Chapel tell us that the, now lost, lower frescoes told stories of Saint John the Baptist; the, still visible, scenes above show apparitions of Saint Michael Arcangel; and that the scenes culminated in the, partially preserved, apse with the triumphant Christ surrounded by choirs of angels.

The scenes of the apparitions of Saint Michael in the form of a bull, clearly visible from the mildly alarming height of the walkway, offer a glimpse into the mood of Bessarion’s Roman years. Saint Michael is the warrior angel, protecting mankind from evil, and guiding him towards salvation. In this context, the protection the arcangel offers is undoubtedly against the threat posed by the Turks who had seized Constaninople ten years before painting began, and which had so deeply scarred Bessarion.

Both scenes refer to visions of the saint which would lead to the foundation of important sanctuaries dedicated to his veneration. The left-hand scene shows the apparition of the arcangel as a bull at the cave of Monte Sant’Angelo near the city of Siponto on the Gargano peninsula in Puglia. The walls of Siponto are clearly visible in the background. The vision is said to have taken place during the reign of Pope Gelasius I (492-496) and tradition says that when Saint Michael appeared in the form of a bull, the arrows fired by the archers who sought to kill him were reflected back at them. In the foreground, on the left, an exquisite archer in green tights and a purple shirt prepares his bow, anchoring it with his left foot.

Archer. Detail of left-hand panel of St Michael scenes.

Something in his pose, and the tights, reminded me of another figure, on a relief carved for a monument to the Emperor Marcus Aurelius thirteen centuries earlier and subsequently “recycled” in the attic level of the Arch of Constantine.

Similarly the elegant candelabra which divide the scenes can clearly be seen to derive from the study of Roman imperial decoration, twenty years before Filippino Lippi would use a similar motif at the Carafa Chapel of Santa Maria sopra Minerva.

The right-hand scene shows the French legend of the apparition of Michael, once again in the guise of a bull, at the gulf of Saint Malo in Brittany, in the dream of Saint Aubert. Aubert, bishop of Avranches, is shown in the centre wearing a mitre and opulently dressed. The sanctuary of Mont Saint Michel clearly visible in the background, he stands on a beach littered with shells, a reference to the island which is accessible from the coast by a causeway during low tide.

The scene would seem to refer to Bessarion’s contemporary and impassioned attempt to involve Louis XI of France, then the richest and most powerful state, in a final crusade which would seek to reclaim Constantinople, in the hands of the Ottomans since 1453. Bessarion hoped to achieve what the Council of Florence had been unable to conclude nearly twenty years earlier, and reunite the Latin and Greek congregations. This is represented by the choirs of monks on the right; the Franciscans in the background wear brown robes, while the monks in the black robes are Basilian monks, followers of the fourth century Saint Basil the Great, the order to which Bessarion himself belonged, and here representing the Eastern Church. Further emphasizing his hopes that Louis would come to the rescue, Saint Aubert is shown with the features of the French king. The bull, in the upper right, is significantly shown tethered to a tree; if Michael represents the struggle of piety against evil, here he is blocked by French immobility.

Behind the bishop, a damaged section partly obliterates the face of a future titular cardinal of the church; dressed in purple is Giuliano della Rovere, the man who would become Pope Julius II. To the left of him, in profile, and wearing the red robes of a cardinal is Giuliano’s uncle, Cardinal Francesco della Rovere, confessor of Bessarion, and the future Sixtus IV, his fierce ambition palpable in the lines of his taut jaw.

Detail. Right hand panel of St Michael scenes showing Francesco della Rovere (left) and Giuliano della Rovere (face partially damaged)

As I left I told the lady at the door how pleased I’d been to finally see it, wished her a good lunch, and stepped out of the shadows of the 15th century and into the bustling heart of Rome on a bright, crisp Wednesday in late January.

Bessarion Chapel, Basilica dei SS. Apostoli, Piazza SS. Apostoli. Open (in theory): Mon – Sat 9am-12 noon. Four euros.