When Garry Sobers smashed Malcolm Nash for an historic 36 runs off six deliveries in 1968, cricket's Everest was finally conquered.
Never achieved before in more than 150 years of the game, this incredible feat of hitting six sixes in an over would go down in history as one of sport's most iconic moments.
But what happened to the world's most famous cricket ball, despatched repeatedly by West Indies captain Sobers as he played for Nottinghamshire in Swansea?
In 2006, the ball supposedly used fetched a record £26,400 at a Christie's auction house, accompanied by a certificate of provenance with the all-rounder's signature.
Nash, however, insisted the Duke ball sold at auction wasn't the one bowled. He said the ball he had bowled 38 years prior was manufactured by Surridge, prompting broadcaster Grahame Lloyd to launch an investigation into the mysterious sequence of events leading to the sale.
As part of his campaign to get Christie's to admit their alleged error, Mr Lloyd will give a talk at Topcroft Cricket Club later this month and divulge one of the sport's most fascinating tales.
'I have no doubt that ball sold in auction wasn't genuine,' said Mr Lloyd, who appeared on Test Match Special last summer to explain why the Duke was a wrong 'un.
'All I would like is for Christie's to admit they made a mistake. They keep saying they have the certificate to prove this was the ball bowled to Garry Sobers 51 years ago.
'I went on the airwaves last year for a 15-minute interview with Jonathan Agnew on TMS and used the opportunity to make an appeal to their global president, Jussi Pylkkanen.'
In celebration of the 50th anniversary milestone, Mr Lloyd spent last year touring literary festivals and cricket clubs across the nation with a talk entitled 'Fifty Not Out: The Six Sixes Revisited'.
During his visit to Topcroft at 7.30pm on Thursday, March 28, he will again recall the bizarre tale of the 'wrong' ball using meticulously collected evidence, poetry and song.
Following his appeal to Christie's, Mr Lloyd says the auction house are 'following a very clear and direct line of enquiry' as their re-investigation into the ball's sale continues.
'One of the reasons I'm carrying on doing this is because I've had such a fantastic response from audiences and reviewers,' added Mr Lloyd, whose book - 'Howzat? The Six Sixes Ball Mystery' - was published in 2013.
'I am hopeful that this matter can be resolved as soon as possible.'
Tickets for the event, priced at £7.50 for adults and £4.50 for concessions, can be bought from helen.brownlee@outlook.com.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here