VISUAL ARTS The Padshahnama, Buckingham Palace, London; Cassiano dal Pozzo's Paper Museum, National Gallery of Scotland, Edinburgh

Two different exhibitions, one currently showing in London, the other just opened in Edinburgh, offer a rare glimpse of the fantastic treasures that lie hidden in the Royal Library at Windsor. At first glance, the shows seem very different, one Indian, the other Italian, but both groups of work date from the 1620s and 1630s and both entered the Royal Library during the reign of George III some 150 years later. In both, the hand of the artist was deemed less important than the subject he depicted and both testify to the extraordinary depths of the Royal Collection.

The first, "The Padshahnama", at the Queen's Gallery, Buckingham Palace, is an exhibition of 44 exquisitely illustrated pages depicting scenes from the life and court of Emperor Sha Jahan, ruler of the Mughal Dynasty from 1628 to 1658. He was an extravagant patron whose commissions included the Taj Mahal and the great forts at Agra and Delhi, as well as a book such as the Padshahnama to record every ten years of his passing reign.

This, the first of them, is one of the world's most glorious illustrated books, and sadly the only one of Sha Jahan's manuscripts to have survived intact. It was given to George III as a gift from the Nawab of Lucknor in 1797 and in the last 200 years has hardly ever been out of the Royal Library. The current exhibition presents a unique opportunity to see all 44 pages, showing fantastic scenes of feasting and fighting, unbound for the first time in their 350-year history.

"Cassiano dal Pozzo's Paper Museum", at the National Gallery in Edinburgh, is not quite such a unusual event (a version of the exhibition was shown at the British Museum in 1993) but it is spectacular nonetheless. Dal Pozzo was a Papal courtier, a friend of Galileo and above all an inquisitive and extraordinary collector of drawings and watercolours. His Museo Cartaceo, or paper museum, comprised a staggering 7,000 drawings and prints and was a sort of visual encyclopedia of both the ancient world (architectural remains, mosaics and wall paintings) and the discoveries of his own time - all manner of animals, vegetables and minerals.

The most interesting are often the most peculiar; the collection becomes a two-dimensional cabinet of curiosities containing, for example, a coconut with a human face, a mutant lemon, a grotesque pineapple, or a splendidly curious print of owls on ice skates. All but one of the 82 works in this selection are unsigned, but many of the best watercolours are thought to have been by Vincenzo Leonardi, whom Dal Pozzo commissioned to record the natural world in all its detailed beauty, be it the head of a pelican or a page of coloured gemstones.

The most striking thing about these works is their fresh colour and superb condition, suggesting that not too many Royal hands have touched them since they were bought by the King in 1762. It is now the Queen's Paper Museum - one wonders if anyone in the Royal family ever looks at it, or at the Padshahnama. Either way we should be grateful that they are sharing them with us now.

'The Padshahnama - King of the World',

The Queen's Gallery, Buckingham Palace, London SW1 (0171-799 2331).

To 27 April

'Cassiano dal Pozzo's Paper Museum',

National Gallery of Scotland, The Mound, Edinburgh EH2 (0131-556 8921). To 8 June