Norwich Castle Museum's new exhibition tells the story behind one of its most extraordinary paintings and the famous family which owned it, with the help of star loans from internationally-famous museums and private collections. Trevor Heaton reports.

Norwich Evening News: Pietre dure table-top, unknown artist, Florence, c1625, with coats-of-arms, c1638, stone inlay including lapis lazuli, chalcedony, red jasper, agate and amethyst, on black Belgian marble groundPietre dure table-top, unknown artist, Florence, c1625, with coats-of-arms, c1638, stone inlay including lapis lazuli, chalcedony, red jasper, agate and amethyst, on black Belgian marble ground (Image: Archant)

Once seen, never forgotten. The Paston Treasure, a startling smorgasboard of 17th-century bling, is one of the star attractions at Norwich Castle Museum and Art Gallery.

In the three generations since the painting came into public ownership this huge artwork has astonished and intrigued visitors in equal measure. For, despite its rich colours and its 'in-your-face' depiction of wealth and possessions, this is a work which seems full of secrets.

It has. This painting, created for the famous but doomed Paston family in the early 1660s, really does have secrets – dozens of them.

Until now, that is. For the new exhibition The Paston Treasure: Riches and Rarities of the Known World – running from June 23 to September 23 – will unpick many of these mysteries, with the help of expert input and stunning artifacts from around the world.

The exhibition, being organised in partnership with the Yale Center for British Art, will reveal more about the painting and the extraordinary Norfolk family which commissioned it than ever seen before.

This international-standard exhibition features 130 objects drawn from museums from around the world, including the British Museum and The Met in New York. Exhibition-goers in the United States have already had a chance to see it; now it's our turn.

There is so much to see in the painting that the eye hardly knows where to begin. A young African boy servant and a mysterious girl, her skin now seemingly almost eerily white. Thirteen beautifully ornate cups in gold and silver. A globe. Musical instruments – including lute, bass viola da gama, recorder – and flora and fauna (a lobster, monkey and parrot) and more, lots more.

It's almost too much to take in. Which would be apt because the Pastons were a family which loved possessions, wealth and status to such an extent that in the end they collapsed into spectacular bankruptcy.

The painting seems like the product of an artist with a particularly lurid imagination. Nothing like this could ever have really existed, surely? But that is the amazing thing: it did. Every single one of these objects was painted from life.

How do we know? Because, miraculously, five of the objects have survived – and they are being brought together with the painting which depicts them for the first time in more than 350 years. They are a pair of silver-gilt flagons, a Strombus shell cup, two unique nautilus cups and a mother-of-pearl perfume flask. There may be more to find, scattered across the world's museums and private collections.

'Most people in Norfolk think of it as just a 'quirky little painting' but it's actually world-famous,' said Dr Francesca Vanke, exhibition co-curator. 'It really is unique.' The painting, along with the objects it depicts, was once part of the contents of Oxnead Hall, the Paston family's vast Norfolk mansion. 'Along with Raynham Hall and Blickling it was one of the three great houses in Norfolk,' Dr Vanke, Keeper of Art and Curator of Decorative Art, explained.

Those two have survived, but Oxnead Hall hasn't. Well, apart from the (relatively) small fragment which survives and still bears the name. The fact that this fragment is in itself magnificent, the sort of drop-dead-gorgeous stately pile which has Country Life subscribers weeping with envy, gives you a clue as to what the original must have been like.

This Oxnead Hall had 80 rooms, most stuffed with paintings, sculptures, objets d'arts and the like. After the 1732 bankruptcy the hall rapidly crumbled away, but an painting by John Adey Repton from around 1809 conveys something of its glory.

But the family had actually parted ways from The Paston Treasure a generation earlier. 'The painting came into the family's possession in 1709, when Captain John Buxton bought some of the contents of Oxnead Hall,' Dr Vanke explained. 'We know because of the sale inventories – it's pure chance that these things survive.' It was one of 73 paintings sold by the increasingly cash-strapped Pastons.

The bulk of the estate would be sold off in 1732 when William, the second Earl, went spectacularly, irredeemably, bankrupt, owing the equivalent of £16 million in today's terms.

'This painting was donated [to us] by the Buxton family just after the Second World War. They had already given us some things. The family were not living in Norfolk any more by the 1930s – they were down in Wiltshire – but their ancestral home was in Norfolk.'

By the time the Buxton family donated the painting it had been in the family for almost 250 years. Time had not been kind. The colours were dulled by a thick layer of dark varnish. '[The donor] Mrs Maud Buxton didn't think it was of any artistic value at all. It was this dim, manky old painting.'

It was displayed at Strangers' Hall in Norwich for a while, but was also loaned out for exhibitions. It was only after being cleaned for one of these loan exhibitions that its full glory became apparent.

And then the questions began… who painted it? For which Paston? And when? The link between the painting and the treasures it depicts has long fascinated researchers. In the early 1990s Robert Wenley wrote a paper on it. And both Dr Vanke and her predecessor as Keeper of Art – Dr Andrew Moore - have long been 'hooked'. But being a regional museum (albeit one which we know punches well above its weight) it has been a tricky task. 'It's hard [for us] to bring together large amounts of objects, resources and scholarship. We needed greater resources than we could manage.'

Step forward the Yale Center for British Art. Both Andrew and Francesca have done scholarships there, and discovered that experts at the centre were just as fascinated by the Paston Treasure as they were. That said, pulling everything together has taken years of hard work and research. Although Andrew left in 2011, he has remained closely involved in the project and is a guest curator.

Thanks to the involvement of the Center, Francesca and Andrew have been able to draw on worldwide expertise. Specialists have been able to identify some individual makers. An exquisite fob watch, for example, turns out to be the creation of the delightfully-named French watchmaker Josias Jolly.

We now know the painting must have been created in the first half of the 1660s, early in the Restoration, when conspicuous consumption was the order of the day. It must have been commissioned by either Sir William Paston, a great traveller and collector who died in 1663, or his son Robert (1631–1683), who was to be created Earl of Yarmouth in 1679. The painting would have been admired by Charles II on his visit to the house in 1671 (a family member married one of the king's many illegitimate children).

Although much has been discovered in the painting, the identity of its artist (known as 'The Master of the Paston Treasure' to researchers) remains elusive. From its style, we can be pretty sure he – it was probably a he - or she was from the Low Countries. 'The style is un-English – very, very un-English,' Dr Vanke added.

The family had a house in London and retained its original estates at Paston, but Oxnead was where their most precious objects were kept. The Master would have been summoned to Norfolk, painting the objects (and people) one by one. 'It's clear that there was one hand at work here, with not much time lapse between the elements,' Dr Vanke explained.

Research has now uncovered another painting, showing a monkey and a very similar parrot, as being by the same hand. Frustratingly, that painting is not signed either. 'I'm not sure that we will ever know who it was,' she added.

That is not the only enigma in the painting. It is not just a brazen collection of expensive objects, but is also full of hidden meanings. 'It's like a code that various people could read at the time [of its creation] but is not at all clear now. You could read an awful lot into it.'

Modern science has come into play too, revealing more secrets.

Alongside the painting are those 130 objects. One of the stars of the show is a 'pietre dure' table top, made in Florence around 1625. We know it belonged to the Pastons because their coat of arms was added around 1638.

The table was sold at auction a few years ago and disappeared into a private collection. But Frances has been able to persuade the buyer to loan it to Norwich. 'I'm very excited about this,' she said. No wonder – not only is it an object we can tie in to Oxnead Hall, but we even know exactly where it was in the house (in the 'Fine Closet [actually a room] next to the Best Chamber').

And how did Sir William display it? With an array of stuffed crocodiles hanging overhead, of course. The Pastons never did anything by halves.

The Paston Treasure: Riches and Rarities of the Known World runs at Norwich Castle Museum and Art Gallery from June 23-September 23. It will also feature a programme of events, including expert talks. Check out www.museums.norfolk.gov.uk/norwich-castle for more information.