It separates the majestic from the merely superior. It's why Nicklaus is in that list above but Tiger Woods, the blonde-waitress-loving conqueror of all except a marital breakdown, isn't. Best (even with character flaws) is there, Diego Maradona isn't - thanks to the helping Hand of God. Borg, with his quiet dignity, makes it but arch-rival John McEnroe and his histrionics doesn't. Mark Spitz, the famed Olympic swimmer, is in but Michael Phelps - who broke all his Olympic medal records but who has had unseemly brushes with drugs and alcohol - isn't.
Most make the mistake of claiming Snell as the only athlete to do the 800m-1500m double in a single Games. There have been four others - Britain's Albert Hill in 1920 at Antwerp, Russians Tatyana Kazankina in 1976 at the Montreal Olympics, and Svetlana Masterkova at Atlanta 1996 and Dame Kelly Holmes of Britain in 2004 at Athens.
Hill's achievement (he also won silver in a long discontinued event, the 3000m teams) was too long ago to make a dent in public consciousness now. Kazankina's career ended abruptly when she refused a drugs test. Masterkova and Holmes, fine athletes with their own remarkable stories, never dominated in quite the way Snell did.
The real majesties of sport command through sheer ability. Psychological pressure, yes, although it's exerted simply by being there. Nicklaus never had to rely on dressing in black and maintaining an intimidating, surly presence as Woods did, barely speaking to his playing partners.
Ali played mind games, of course, but with such mischievous and clever execution it was almost impossible to take offence, even when he was being entirely offensive. Ali changed the world, not just sport, but he would taunt opponents, making them want to hurt him so badly they would over-reach, bringing them into range for a lightning Ali counter
He didn't just play on favourite causes - he baited Floyd Patterson for being the "white man's champion" (all the while proclaiming his own 'prettiness' as a lighter-coloured black man) and he greeted one opponent of significantly darker hue in the ring with the words: "Oh man, you black. You blaaaaaack!"
He systematically destroyed Ernie Terrell for calling him Cassius Clay after Ali had changed his name. Ali deliberately prolonged a bout he could have ended earlier, baiting and punishing Terrell, keeping him just in the bout so he could hurt him more. But even in that vengeful display there was majesty in his precision, even if prompted by cruelty.
Snell ruled with his physical presence and kick. Opponents knew it was coming but could do little about it - like a Nicklaus surge. Snell abdicated when he was 26 - the same age as Borg - and Leggat's piece included an almost-hidden piece of explanation from Snell, now 75. He said he didn't particularly like athletics but it fed his hunger for success.
"It was a vehicle to satisfy my need for achievement. I'm happy to admit that now." he said. "My background was ball games. I was brought up on tennis, cricket, I liked badminton and golf. They were games I enjoyed more than running. But what I enjoyed about running was the success ... I was married by this time, wanted to start a family and enjoyed other pursuits. For me, running was not a No1 sport; it just happened to be the one I was best at."
Majesty even though he was not to the manor born.