One of the most important factors affecting value at auction can be the historical significance of an item – copies of the US Declaration of Independence are among the best examples of this. Often overlooked, however, are those seemingly unimportant pieces of ephemera that cast light on largely forgotten episodes from our past.

I was reminded of this by a news article about two small sheets of paper consigned for auction that recall the 1740 frost fair on the Thames. Each expected to fetch around £1500, they detail all sorts of activities on the ice as the river froze over: football, horse racing, ox-roasting, merry-go-rounds, skittle alleys and puppet shows.

It’s hard to imagine the Thames freezing over now – in fact since the building of the comparatively modern set of bridges with their pontoons, this has been made much more unlikely. No one alive now can remember these events, so even the faded memory is lost, which makes these written records so much more important.

One of my favourite examples of this is a 15th century French illustrated manuscript that appears to show an early game of cricket. The known history of the game dates back to the late 16th century in south east England, although it is thought to have its origins in Anglo Saxon times. What if another document appeared that forced us to re-attribute its invention to another country?

This time of year the news is full of headlines talking about Contemporary artworks that have sold for tens of millions of dollars at auction in New York. Andy Warhol, Jeff Koons, Jackson Pollock and others whose masterpieces can attract prices that dominate the upper end of the art market obviously earn their moment in the limelight, and every national and international magazine and newspaper column dedicated to the art and antiques market will be full of news about these sales.

Far less often they also report what is going on at the bottom and middle of the market. Selling a decent Victorian watercolour at £150 is just not news, and I get that. But we should not forget that for all the stratospheric sums paid for the trophy Contemporary works, it is the comparatively workaday pieces that oil the wheels of the global art market, attract new buyers for the first time and form the bedrock of the grander sales.

Think about the billions of pounds worth of stuff sold on eBay each year. A global player for the best part of 20 years now, it has also delved into online auctions of art – albeit with mixed success. But it all started because a collector of humble Pez sweet dispensers wanted to be able to trade them over the internet. It’s another case of mighty oaks growing from tiny acorns. So next time you read about a $50 million Hockney, remember that £150 Victorian watercolour and the indomitable roots of the great world of auctions.

As I have written before, one of the most important factors in valuing items for auction is their historic associations. This especially true for film props and costumes and musical instruments. A guitar played by John Lennon or Paul McCartney would be valuable; a guitar owned by them even more so. However, a guitar used by either of them at one of their most famous concerts, such as the 1965 Shea Stadium event, or for recording their most famous hits, would be worth considerably more because of its iconic status. So it comes as no surprise that the auction record for a Beatles-associated instrument is the $2.1m that the late singer George Michael paid for the piano on which John Lennon wrote his solo hit Imagine.

I thought about all this when that a dress once worn by Princess Diana would be coming up for sale. In itself, this is not such a rarity; a number of gowns worn by her have sold at auction over the years, ranging in price from tens of thousands to hundreds of thousands of pounds.

However, apart from the famous wedding dress, I can’t think of a more iconic dress than the Victor Edelstein creation the Princess wore to a White House gala dinner in 1985. Why? Because she was wearing it when she made headlines all over the world at the event by dancing with the actor John Travolta to music from the film Grease.

The dress previously sold in 2013 for £240,000. The estimate this time? £350,000.

There’s iconic and ICONIC!

Last week I wrote about brown furniture and how the fact that it is so competitively priced these days creates an ideal opportunity for getting young people looking to furnish their first home into the saleroom.

Of course, that presumes that just because they are young they have no idea about the auction process – wrong!

As I have discovered in recent years, while Generation Z have moved on from the millennial obsession with Facebook and tend to favour Snapchat, a huge number of them are also very much at home trading clothing and other possessions via apps like Depop.

The online trade in collectable trainers – especially limited edition versions issued by celebrity musicians and sports stars in the US – is now worth billions of dollars a year. What we are seeing here is the evolution of auctions and dealing platforms where teenagers are becoming as adept at negotiating, assessing value and spotting flaws as well-seasoned art and antiques dealers and collectors.

This tells me that chasing a bargain is a strong part of the human psyche and the auction process is one of the best means of meeting that need. Whatever the age and the technology, then, the essentials remain the same. And that’s rather reassuring for industry professionals, like me, who have been around for a bit.