The Colour of Heaven, by James Runcie

Beyond the blue horizon

When 30-year-old Teresa collects her foundling child from a Franciscan monastery in the Venetian lagoon, the monks avert their eyes to avoid temptation. Their action establishes both the tone – tender and gently comic – and the central metaphor – vision and blindness – of James Runcie's second novel. A quest for spiritual enlightenment and earthly love, it is set in Italy, China and Afghanistan in the early 14th century.

While the monks have a choice as to what they see, Paolo, the child in question, has none. The older he grows, the clearer it becomes that he suffers from severe myopia which prevents him from taking up his father's glass-blowing trade. On the other hand, his heightened near-sightedness and acute sensitivity to colour attract the attention of Simone, a Siennese painter, who offers him a place in his workshop.

Shortly after Paolo's arrival, Simone wins a prestigious civic commission to paint a fresco of the Coronation of the Virgin in the Palazzo Publicco. Simone aims to capture "the divine stillness – the life of the spirit on this earth. A foretaste of heaven". Essential to his purpose is the use of a miraculous blue, rumoured to be created from ground lapis lazuli found in the East. Simone sends Paolo, together with Jacopo, an elderly Jewish merchant, to find the stone. As in so much of the quest literature contiguous with this story, the ostensible object of the search is of less importance than the actual one: Paolo's discovery of love for himself, for a woman and for the world.

Runcie skilfully and economically delineates his late medieval setting, where a 60-year-old man is among the oldest that Paolo has ever seen, where hucksters tell fortunes from the direction and duration of a sneeze, and where growing a beard is recommended as a remedy against lust. As might be expected from the author's background (his father was Archbishop of Canterbury), the religious detail is particularly salient, whether the monks who sleep in their coffins in preparation for the Day of Judgement or the worship of saints such as Lucy, who drowned in a vat of boiling urine, or Paula and Uncumber, who escaped rape by spontaneously growing moustaches. The most resonant image is that of the Christian Paolo, the Jewish Jacopo and their Moslem guide, Salek, riding in perfect harmony through the desert. Paolo's subsequent encounter with a Buddhist monk, however, takes ecumenicism a step too far. His contemplation of a leaf and chanting of "om" comes across as less 14th-century than New Age.

As the story draws to an end and Paolo obtains a rudimentary pair of spectacles, Runcie overloads his central metaphor, ringing too many changes on the theme of sight and insight. At the same time, the nature of his actual impairment remains frustratingly blurry. Overall, however, the novel shares much of the serenity and luminosity of the painting at its heart.