By Ian Youngs BBC News Online entertainment staff

The Queen opens an exhibition of the most important art and artefacts from the Royal Collection at The Queen's Gallery on Tuesday, 21 May.

Bringing together works accumulated by monarchs over five centuries, the Royal Treasures exhibition is the first to be housed in Buckingham Palace's rebuilt art gallery.

The exhibition runs until January 2003

Described as the "creme de la creme de la creme" of the 500,000 objects in royal possession, the exhibition sees Rembrandt, Da Vinci, and Vermeer share space with jewels, furniture and elaborate ornaments.

The elegant new Queen's Gallery used to be just one room and a corridor - but now has a grand entrance and two new rooms where a kitchen and roof used to be.

The space is stately but not intimidating, and mixes formal features with more eccentric touches.

It takes a while to realise that the plant pots have been topped up with piles of apples, and Buckingham Palace dog bowls are an unusual addition to the merchandise range.

The three main exhibition rooms - supplemented by a couple of other cubby-holes - have been decked out in regal but attractive hues of red, green and blue.

Van Dyck's portrait of Charles I dominates the first room

And in the 450 exhibits, we get an overview of royal tastes down the years - from Charles I's Holbein to Lucian Freud's portrait of Elizabeth II.

In between come some of the Royal Collection's many Da Vinci sketches - with aged and ragged edges - plus works by Canaletto, Hogarth, Gainsborough and Monet.

Dominating the first room is Van Dyck's huge portrait of Charles I on horseback - but the gallery also gives prominence to a royal attic's worth of odds and ends collected over the centuries.

Just through the first door, attention is drawn away from the Rembrandt and the Hals, and towards two very odd earthenware vases collected by Mary II.

The hexagonal, pyramid-like towers, from Delft, Holland, have 54 spouts into which tulips could be placed.

Queen Mary II had a passion for pottery

Unfortunately, the way these objects are arranged around the paintings just gives the rooms a feeling of clutter - each deserves its own space.

But there are some smaller rooms and cabinets dedicated to artefacts like Indian jewels and over-the-top golden candle-sticks, table ornaments and altar plates.

One cabinet houses one of the oldest printed books in the world, the Mainz Psalter, along with the Queen's bible from 1953 - which looks more like a school textbook.

There is also the crown that the Queen wears on stamps and coins - and seeing it hung with its accompanying earrings and necklace conjures an image of a young Elizabeth, despite the fact that it was made for George IV.

Some of the exhibits do have revealing stories behind them and can shed light on the last 500 years of monarchy.

Queen Victoria commissioned a portrait of Prince Albert's greyhound

A painting of Prince Albert's favourite dog, Eos, along with his master's top hat and gloves, was commissioned as a Christmas present from Queen Victoria in 1841 - and reveals the warmth and affection of their relationship.

But the tales behind many pieces are not so obvious, unless you trawl through the �40 catalogue.

We are not told that Mary II's liking for porcelain led to her single-handedly inventing a new style of displaying it.

Theme

And Faberge's miniature farmyard animals become a little more interesting if you find out that Russian sculptors spent months at Sandringham studying the animals' behaviour after the pieces were commissioned for Queen Alexandra's birthday in 1907.

Unlike many galleries housing such national treasures, there is a common theme running through this exhibition - royalty.

The Royal Treasures could have told the story of the monarchs through their art - but it is too crowded and self-conscious for that, and sacrifices a fascinating dimension.

Despite that, it is still a collection of great works that rarely come together for a public airing.