NOT many men, and fewer women, have been accorded the cognomen "the Great". In classical history, one thinks of Alexander and Pompey; but, surprisingly, Augustus and other emperors never gained the appellation. The Mongol ruler Timur the Lame (c.1336-1405) was demonised by Christopher Marlowe in Tamburlaine the Great.

European monarchs fare little better, although the only British sovereign so recognised is Alfred of the West Saxons. One wonders whether he features in Michael Gove's quixotic curriculum. In Russia, Peter and Catherine stand pre-eminent, of course; and Charlemagne (d. 814) proved something about a unitary Europe. The "Sun King" took the name for himself (on the victory arch of the Port St Denis you can still read the gilded bronze inscription to "Lodovico Magno"); but Louis the Great more commonly refers to the earlier Hungarian King of Croatia (1342).

In the Western Church, two pontiffs have made it. Alessandro Algardi's outstanding relief sculpture in St Peter's, Rome, of the late 1640s, shows the Apostles Peter and Paul, meat cleaver and sword in hand, confronting Attila the Hun at the behest of Leo the Great (d.461), the first pope to be interred in the new basilica. Gregory the Great dispatched Augustine to Canterbury. Supporters of the process for canonising Karol Wojtyla have taken to advocating John Paul the Great.

In Muslim culture, such a designation would be little short of blasphemous. God, and God alone, is Great. This exhibition, staged by the Fondazione Roma in a palace along the Corso in the heart of the city, explores the conundrum that Allahu akbar, the traditional cry that God is the Greatest, can also mean Akbar is God.

The third Moghul emperor, Jalaluddin Muhammad, called Akbar (1542-1605), was a descendant of both Genghis Khan and Tamburlaine. Akbar was only 13 when he succeeded to the throne at his father's unexpected accidental death, and he achieved his full majority at the age of only 17.

While he could be ruthless, he was also noted for his generosity and civility. As a Muslim, he married a Hindu princess as his first wife, and, as he expanded his empire northwards to include Pakistan and parts of Afghanistan, he appointed governors regardless of their nationality, ethnicity, or religion.

Although he remained illiterate throughout his life (it is suggested that he may have had an acute form of dyslexia), he met sages and scholars every Thursday evening to discuss a "divine Faith", a syncretistic and religionless form of worship which, in 1582, embraced the empire. Three years before, in the famous mahzar, Akbar had been declared the supreme governor (imam-i-adil), with authority over the teachers of the faith. As amiru'l muminin, he was all but Caliph as a guide to the faithful.

To some, particularly Pakistani, Muslim historians, this open tolerance and encouragement of all other faiths has been denounced as apostasy; but others recognise that pragmatism and a sound business sense lay behind the dialogue and toleration.

At Court, Hindus and Muslims wore the same dress, differentiated only by whether it was tied across the left or right side of the chest; and from 1580, the Court welcomed Roman Catholic priests. Between 1542 and 1552, much of South India experienced the Jesuit missions, led at first by Ignatius Loyola and Francis Xavier, and Akbar encouraged them to enter into his empire.

We glimpse much of this civilised and civilising tolerance in the pages of illuminated manuscripts that richly inform this exhibition. In one watercolour, painted on cotton and dating to 1578-80 (Paris, Fondation Custodia), two turbaned mullahs are seen debating. In another, from the British Museum, attributed to the Hindu artist Basawan, the prophet Elijah comes to the rescue of a prince, Nur al-Dahr, who is about to drown. The apocryphal tale is recounted in The Adventures of Hamza, the Prophet's paternal uncle.

In 1582, Akbar set Hindus and Muslims to translate the Mahabharata into Persian, the language of the Moghul court. Just how equal each faith was is teasingly asked in a watercolour from Philadelphia's Free Library. The Brahmins are seen seated on a gingham cloth as they debate from a scroll. Yet, in the more important part of the pic- ture, three mullahs, each sitting on a richly decorated carpet with their tesbih, their prayer-beads, write on a codex. Two servants fan them, a privilege not accorded the Hindus.

To Western eyes, perhaps the most interesting aspect of the exhibition, which includes coins and furniture - an inlaid ivory-topped table from Gujarat depicting the Blessed Sacrament in a monstrance censed by angels turns out to incorporate an altar frontal - is the accommodation of Christian iconography.

After the first Jesuit mission to the Mogul court at Fatehpur Sikri, the circulation of European prints made possible first-hand encounters for Indian artists in the imperial atelier.

Twenty years later, during the third Jesuit mission, to the court at Lahore, Fr Gerolamo Saverio SJ and Abd al-Sattar Ibn Qasim Lahori worked together to produce The Mirror of Holiness (Mir'at al-quds), which offered a redaction of the Old and New Testaments.

One illustration, from a copy that was lavishly painted, probably for Akbar's son Salim, depicts the surprise of the disciples encountering the Samaritan Woman at Jacob's well (John 4.27). It was painted by Manohar, Basawan's son, who copied a picture from Geronimo Nadal's Evangelicae Historiae Imagines, which was first published posthumously in Antwerp in 1593.

The artist has been faithful to the original; but the disciples are now shown as Europeans seen through oriental eyes. The youngest, in a tunic with a ruff and trousers, holds a handbag from which, no doubt, money had been paid for the food that they had gone to fetch, while the apostle in front of him has a soft cap. Similarly, Elizabethans litter the ground at Calvary in a scene of the crucifixion by Keshav Das, which clearly derives from a Flemish prototype (British Museum 1983, 1015-01).

The winged Evangelist St Luke, in an earlier manuscript illumination (Paris, Fondation Custodia) that derives from a German woodcut by Hans Sebald Beham (1500-50), appears in a red cloak with multi-coloured wings. But instead of the bull lying behind him at his feet are two greyhounds. Perhaps the change was a conscious way of avoiding giving offence to Hindus by removing a recognisable image of Nandi.

The catalogue and the exhibition taken together are a contribution to deepening our knowledge of the profound humanity and diversity of one inspired ruler whose example might speak in our own day. 

"Akbar: The Great Emperor of India" is at the Fondazione Roma Museo Palazzo Sciarra, via Marco Minghet-ti, 22 Rome, Italy, until 3 February. Phone 00 39 06 697 645 599. Open 10 a.m. to 8 p.m. daily, except Monday.

www.fondazioneromamuseo.it