Of course many other countries have far greater holdings of their own culture which Britain could never match – Italy for example – but overall a combination of the accidents of history and serendipity mean that the breadth, if not always the depth, of material culture housed in these islands is prodigious. From the seventeenth-century and on the Grand Tourists who followed well trodden paths – the Scots tended to go to Northern Europe, the English to the South – to Empire builders, the military, and the businesses from the East India Company to, say, the Hongs of Hong Kong, for example Jardine Matheson, Swires, a lot of stuff has come back. And still invisible are countless private holdings, historically fuelled by families who have worked all over the world, and currently aflame with new collectors as London invents itself as the world’s art capital. And much of the last will eventually enter the public domain.

The result is a complicated and intricate web of public collections, that is, artefacts on public view, available to be visited – and seen. Of the thousands that exist, each museum, gallery, mansion and industrial site, have different histories, trajectories, journeys, buildings, roles, and rules, and often complicated relationships with the public purse, from the fiscal privileges of incorporating as a charity to actual local, regional and national subsidy.

And each is flavoured by the powerful, idiosyncratic, eccentric, determined individuals who have provided the core collections: we tend to think that so much is provided now by public funding but in fact currently all is a complex cat’s cradle of public private partnerships, some quite recent. Yes, the public buys (occasionally, and often moaning as it does) but looking at provenance, most has been given. The charities that subsidise art from The Art Fund (1903) to the Contemporary Art Society (1910) are private. The paintings in the National Gallery and Tate, the holdings of the Victoria and Albert and the British Museum were given by individuals and the great university collections depended on private benefaction: the Hunterian inGlasgow,theAshmolean in Oxford, the Fitzwilliam in Cambridge to name but three. And Britain started early: the Ashmolean dates its initiation to the seventeenth-century, the British Museum brands itself the oldest public museum in the world (1753), and Dulwich, England’s oldest public picture gallery, from 1811, while the Hunterian, Glasgow, is Scotland’s oldest public collection (1807). And even now in the insecurities of straitened times the renewal and expansion of the collections and their housing continue. Tate Modern’s converted power station at Bankside itself only opened in 2000, and now over £200m will be spent to nearly double its size, scheduled for the end of 2016.

In this extraordinary web of material culture two contrasting public collections of international significance which are both relatively recent newcomers in terms of public consciousness and access may make the points most vividly about the continuing ways in which Britain’s collections reach a new audience: the collections could not be more elite, but hundreds of thousands, even millions, visit in person – or on the web.

There is a drawings gallery at Windsor, and two purpose-built galleries, one in the Palace of Holyroodhouse, Edinburgh and another in the vastly expanded Queen’s Gallery at Buckingham Palace, on the site of Victoria’s private chapel, damaged by bombs in the war. The totally new building was designed by the conservative John Simpson, who has rarely envisioned a building that didn’t need a colonnade, or at the least a portico. It was the biggest building project for Buckingham Palace since the new ballroom for Queen Victoria. The Queen’s Gallery was reopened in 2002, the twenty- million cost of its expansion financed by the costs of admissions and the unquenchable desire for merchandise from royal shops.

From its history until the 1960s, the holdings of the Royal Collection have been subject to increasingly skilful exhibitions, usually three substantial offerings annually, accompanied by catalogues, a variety of publications, and a serious catalogue raisonné of the entire holdings in varying categories defined by chronology, media and genre.

The Northern Renaissance Dürer to Holbein is currently on view at the Queen’s Gallery, Buckingham Palace, until 14 April, having already been shown in Holyrood. The strengths of the displays are evident: combined with the extensive catalogue we are provided with a crash course in the history of northern Europe in the period (late fifteenth through the sixteenth-centuries, Holy Roman Empire and the convulsions of Tudor England, the groupings of the Hanseatic League, and so on); the education room has the usual screens for further illustrated information; and on the walls, among the ample display, superb paintings and drawings by Hans Holbein the Younger, a generous grouping of engravings by Dürer, A Knight, Death and the Devil and St Jerome in his Study, among other masterpieces. There are significant contributions by Anonymous and those tantalising artists identified only as being the Master of this place and that – including even The Circle of the Master of the Legend of the Magdalen, with an intricate rendering of the Martyrdom of Saint Ursula. We are reminded of how much scholars and artists, among others, travelled, and indeed kept in touch: on view is the undoubted masterpiece of Quintin Massys’ 1517 portrait of Desiderius Erasmus, a gift to Sir Thomas More. By implication and indirectly we are both shown and told of trade, travel, diplomacy and politics. Tangible goods and intangible ideas both made frequent and at times unexpected journeys. The Royal Collection Trust brings selected holdings into the light, conserved, annotated, noted, contextualised, in endless enjoyable instalments. And the collections, not to mention royal history, inspire others: the highly successful winter exhibition this season at the National Portrait Gallery concerned the older brother of Charles I, and his intellectual and collecting proclivities even as an adolescent learning his swordplay and his classics – The Lost Prince: The Life and Death of Henry Stuart.

The Wallace Collection is also influenced by revolutions and political convulsions, but to its advantage. Hertford House, the mansion in Hertford Square, is home to an inalienable collection of arms and armour, French furniture to rival the royal collection, porcelain, masterpieces of European painting – Poussin, Velazquez, Hals, not to mention extraordinary holdings of eighteenth-century French painting – all set into a score and more sumputously decorated galleries in the eighteenth and early nineteenth- century manner. The dandified, greedy Prince of Wales, George IV would be right at home. The Wallace Collection in all its renewed glory defiantly, richly, makes a virtue of extravagance.

It is the product in part of collecting from the fall out of the French Revolution and Napoleon, the collections of four Marquesses of Hertford, and the last’s out of wedlock son, Sir Richard Wallace, who brought his collection home from Paris after the Franco-Prussian war and succeeding tumult. His widow bequeathed the house and collection to the nation in 1897.

Until recently, although only two streets away from Oxford Street, the Wallace was an all too well kept secret, hardly visited. But in the maelstrom of changing views of what museums and galleries are for – not just the care and conservation of collections, but displays for the public which actually bring the public in – the Wallace has been a star, renovating, refreshing, modernising, redoing, and yes, now replete with shop, special exhibition gallery, courtyard restaurant. It has initiated major scholarly catalogues, rebuilt itself with a lecture theatre, hosts seminars in the History of Collections and collectors, open to the public, and if it cannot lend, it temporarily imports, at times controversially: Damien Hirst, Lucian Freud around the corner from Hals’ Laughing Cavalier. Judicious loans to the Wallace underline the existing collections, and currently on is Murillo at the Wallace Collection. The fourth Marquess liked ‘pleasing’ pictures with the result that the Wallace has an extensive group of Murillo, here punctuated by the loan from one of Britain’s ‘statelies’, Wrotham Park, of Murillo’s Rest on the Flight into Egypt, part of a series (the Wallace has three others).

The Wallace has been open free to the public for over a century, but has only relatively recently started to reach the wide audience it deserves. The Royal Collection for much of its history has been mostly on view to the privileged: now for nearly half a century in various ways its astonishing treasures have entered a public domain.