Taking the papal bull by the horn

God has given us the papacy," remarked Pope Leo X when he first heard of his election. "Let us enjoy it." Enjoy it he certainly did; indeed such was his extravagance that within a year Leo had created, and sold, 1,200 new ecclesiastical offices, as well as squandering both the savings of his predecessor and his own considerable Medici fortune. Wine quite literally flowed in the Vatican fountains. Bullfights filled the day; masked balls occupied the nights. The Pope's table groaned with exotic dishes. One Venetian ambassador described a meal of 65 courses, each course consisting of three different dishes: pies of nightingales breast followed peacock's tongues with cloves and lamprey's fins cooked in a Cretan wine sauce...

Leo craved constant distraction. Dwarves and jesters proliferated; packs of French hounds and flights of Icelandic falcons were imported to fill the kennels and cages of the Pope's Campagna estates. But Leo's favourite distraction was undoubtedly his white elephant, a gift from the King of Portugal, which the Pope housed in the Belvedere Gardens. The present was such a success - and resulted in such valuable concessions to the Portuguese Empire - that soon the Spanish and the Portuguese were competing to find a similar gift.

From this rich historical material Lawrence Norfolk has created one of the most ambitious and inventive historical novels to be written since the death of Robert Graves. The plot revolves around the search for the beast with which both the Spanish and the Portuguese hope to secure a Papal bull authorising the conquest of great tracts of the New World: as the Spanish Ambassador remarks early on in the book, "The Pope craves marvels and prodigies before allies and armies. I tell you a dragon, a gryphon and a centaur would secure Africk, the Indies, and the New World, all three." As with Norfolk's last novel-extravaganza, Lempriere's Dictionary, sub-plots mushroom unrestrictedly across the globe, with rhinoceros-related intrigues from a collapsing monastery on the Baltic Coast, the jungles of Benin, the ruins of the Tuscan city of Prato, and a besieged fort in Goa.

All this is brought to life in bawdy baroque-punk prose of marvellous fluency, overlaid with a gloss of heavyweight erudition encompassing everything from obscure Renaissance sexual practices to the minutiae of canon law. Where else could you come across learned asides on the grafting of greengages, the working of glaciers and the sacred symbolism of the chameleon?

The linking element in all this - apart from the elusive rhinoceros itself - is the sea. The book positively billows with trade winds. Boats are a particular distraction: Viking freighters and byrdingers, dragon ships, scaphas and knarrs, the Papal barge and a Mocambiquan sambuq all sail in and out of the plot.

The Pope's Rhinoceros does have its faults. Norfolk's prose is so effusive, his descriptions so full and fluent, that at times the background is in danger of eclipsing the foreground: at one crucial moment in the plot, when the whole search for the papal rhino is in danger of losing itself in the rainforests of the Slave Coast, Norfolk suddenly heads off on a long discussion on fluvial hydraulics

Lempriere's Dictionary was probably the most internationally acclaimed British first novel to be published for 20 years. If there is a slight sense of disappointment with its successor, that is perhaps inevitable. Norfolk's prodigious gifts are magnificently on display, but there is a severe lack of discipline in the editing: many long-winded or extraneous passages that should have been removed have been left in, and the book is too long by at least a hundred pages. Yet these are small quibbles. For all its faults The Pope's Rhinoceros is still an astonishing achievement, little short of a masterpiece.