Carlo Crivelli, 'Saint John the Baptist', 1476

Crivelli painted two altarpieces for the small church of San Domenico, in Ascoli Piceno in the Italian Marche. Their history is complex and intertwined. A large, two-tiered polyptych was displayed on the high altar, while a smaller altarpiece was in a side chapel.

The polyptych was still standing on the high altar in 1724, but was later dismantled. In the nineteenth century parts of both were sold to a Russian aristocrat, Prince Anatole Demidoff. He mounted them in a grand frame to make a three-tiered altarpiece for the chapel of his villa in Florence. The whole complex is known after him as the Demidoff Altarpiece.

The National Gallery bought the Demidoff Altarpiece in 1868. In 1961 the four saints in the upper tier – originally painted for the small altarpiece in San Domenico – were removed from the main altarpiece. They are now shown separately (Saint Jerome, Saint Michael, Saint Lucy, Saint Peter Martyr).

Exactly how the remaining nine panels were originally arranged is unclear. We know that the Virgin and Child were in the centre, with full-length saints on either side and half-length figures in the upper tier – although not necessarily in their current order. The altarpiece had a predella, now lost, and was topped by a painting of the Lamentation over the Dead Christ, now in New York.

San Domenico was the main church in Ascoli of the Dominican Order. The Dominicans, often known as the ‘Blackfriars’ in England, were one of the two great mendicant or preaching orders founded in the Middle Ages to provide educated preachers in towns and cities. Mendicant comes from the Latin word mendicare – ‘to beg’. Men who joined the mendicant orders took vows of poverty and travelled from place to place, preaching and living on what was given by their listeners. There were few Dominican houses in the Marche, as it was a mountainous, sparsely populated region, and the priory and church of San Domenico fell into decline in the fourteenth century. It was revived by the Blessed Constanzo di Meo di Servolo (d. 1481), who is shown in the altarpiece as Saint Dominic. He restored the priory and commissioned the great altarpiece, raising money from the citizens of Ascoli to pay for it.

In medieval Dominican churches the high altar was usually on a raised dais at the east end of the church. It was separated from the public west end by a tramezzo screen, known as a rood screen in England, so only the friars themselves could get close to the altarpiece. They would have gazed at it for many hours each day while sitting in the choir stalls for the performance of the liturgy, and the choice of saints closely reflects their concerns: preaching, teaching, defeating heresy and the salvation of souls. The Virgin in the central panel was the special protector of the Order. Saint Peter on her right stands for the papacy, which the Dominicans faithfully supported. Saint John the Baptist at the far left represented the idea that salvation could only be achieved by admission to the Church through baptism. On the Virgin’s right are Saint Catherine, whom the friars admired for her defence of the Christian faith against non-believers, and Saint Dominic, the founder of the Order.

In the top row we see Saint Francis, founder of the Franciscan order of preachers. Next to him is Saint Andrew, the first apostle, seen as a role model for preaching to ordinary people. Facing these two saints are Saint Stephen, the first Christian martyr, who like Catherine debated with unbelievers, and finally the great Dominican theologian Saint Thomas Aquinas. The saints all look quite different, ranging from fierce apostles to ecstatic friars and elegant princesses.

In all of them, Crivelli has used techniques such as gilding, punching and incising to make his paintings seem three dimensional and real. He emphasises certain objects, such as crowns and haloes, by building them up with pastiglia so they stand proud of the painted surface, and unites the panels by tooling a damask pattern, like that of a rich fabric, into the burnished gold backgrounds. These shapes and patterns must have shone and flickered in the candlelit nave of San Domenico.