“I am the greatest,” shouted Cassius Clay (Muhammad Ali) in 1963 on his comedy album that is now seen as a precursor of rap and hip hop. It may have been a semi-serious claim at the time, but the world sat up and took notice when he became World Heavyweight Champion six months later, beating the heavily favoured title holder Sonny Liston.

Many consider Ali the greatest sportsman of the 20th century – an amazing claim but one sustained by the strength and individual nature of his character and his ability to tap into the public mood.

In the world of rock and pop memorabilia, for all their worship at the altars of Elvis and Buddy Holly, auction records and the fans have made it very clear that there is no one to touch The Beatles, the most iconic band of all time – a status that they are unlikely ever to cede to anyone else.

Now Roger Federer has announced that he is to auction 20 lots of his match-worn clothing and racquets from his Grand Slam wins on June 23 to raise money for his foundation.

Nadal may have matched his men’s Grand Slam record of 20 titles, and Djokovic may even pass that to set a new record in the next year or so. But the frustrating thing for Djokovic, to whom this means so much, is that the number of titles doesn’t matter because we all know – and he knows – that what makes Federer the GOAT is something that surpasses the results board: that untouchable mix of grace, athleticism and perfectionism leavened by a healthy dose of self-deprecation and the seemingly effortless ability to charm the fans.

So far, Federer is a shoo-in for the greatest sportsman of the 21^st century, proving that, in the end, being the greatest is about character. This auction should be a landmark sale in every way.

With headlines celebrating huge prices for modern collectables like sneakers, comics and plastic toys, the traditional world of fine furniture and silver auctions can seem a long way away. The reality, though, is that at heart little has changed except for current tastes.

People of all ages like to have nice things and they also like to make a bit of money from things they no longer want or need, which other people might appreciate.

The factors that govern values in Pokémon playing cards are little different from those that determine what people will pay for other, older works on paper, especially rarity and condition.

Sometimes people of different generations like the same things without realising it because they call them different names: what younger collectors refer to as vintage posters, advertising packaging and other transitory pieces of design would be called ephemera by the collectors of yesteryear. The trick is getting people to appreciate that ‘antique’ is not dead and gone, it’s simply transitioning as the years go by, along with the terms we use to describe it.

The result is that auction houses have begun to change the way they present their sales calendar and departments to reflect the changing attitudes of the public who tend to think of objects in terms of furnishing and design rather than as academic collectables. Furniture, lighting and works of art sales have now sometimes come together under the title of Homes & Interiors, for instance. And the types of furniture, from the way they are designed to the materials they are made from, have also moved on, with the occasional backward glance as out-of-fashion pieces suddenly become à la mode once more.

What is the most expensive shoes you have ever comes across? A pair of Manolo Blahnik’s? Jimmy Choo’s? No longer, thanks to a pair of sneakers once worn by the rapper Kanye West, which have just sold for a cool $1 million at auction.

These were the first pair of Nike Air Yeezy 1’s ever worn by West and he slipped them on for the 2008 50^th Annual Grammy Awards.

It’s hard to think of something manufactured as recently as 13 years ago as being of such value as a collectable, but it’s a lesson to us all that serious sums are not always associated with rarities from the distant past. In fact, a 2019 report by Cowen Equity Research classifying sneakers as an alternative asset class predicted that their resale market would be valued at around $30 billion by 2030. That’s the equivalent of over half the value of the entire global art market in absolute terms today.

Some auction houses already have departments dedicated to vintage fashion, but it looks as though others will soon have departments dedicated solely to sneakers.

It’s a far cry from the traditional furniture, jewellery, ceramics, glass, silver, books and fine art departments of the past, but times move on. Guessing what other alternative asset classes will emerge to change the profile of auction houses is an interesting game. What’s your prediction?

The death of the Duke of Edinburgh, although anticipated owing to his great age, nevertheless came as a bit of a shock as he seemed to be rallying after hospital treatment.

Tributes have poured in for what was a remarkable life in many ways, from its beginnings among the fading vestiges of European royalty swept away in the First World War and Bolshevik revolution to its completion as the standard setter for royal protocol globally.

Sacrifice, duty, honour and commitment were all instantly recognisable qualities in Prince Philip, who carved a path through life like no one before or since.

He was also innovative, forward-thinking, clever and brave, with little patience for time wasters or laziness.

With so much experience and having been central to so many memorable events as he supported the Queen over almost 75 years, what he saw and heard along the way would make the most fascinating biography. He is said to have kept meticulous records for posterity. If he approached them with the same no-holds-barred acerbic wit that he approached life, then they would be a best seller in the making. Let’s keep our fingers crossed for that.

Meanwhile, such close attention of a royal life like this can also have the power to create new fascination in nascent collectors. Items linked with royalty can already make very significant sums at auction. Reflections on the Duke of Edinburgh’s life may well encourage a new generation of fans to join the fray.