On October 22 2006, Fernando Alonso was on top of the world. He'd clinched a second consecutive world championship at the Brazilian Grand Prix, and with Michael Schumacher retiring it was legitimate to ask whether the Spaniard might go on eclipse his mark for grand prix victories and world titles. With 15 wins and 15 pole positions in his 86 starts, Alonso had the Formula 1 world at his feet.
Almost 12 years later, and he is stepping away from F1 having added 17 victories, seven poles and no more world championships in the subsequent 216 races. It's frankly pathetic that a driver of Alonso's prodigious ability has secured nearly as many seventh places (16) as wins during that time, and that's entirely down to the machinery that has been at his disposal.
Who knows whether Alonso will add to that record in F1, as for every Mika Hakkinen, who headed into a 'sabbatical' but never came back, there's a Nigel Mansell who does. But even if Alonso does return, his F1 legacy is likely to be of a talent wasted. It seems absurd to say that given what he did achieve, and it says much about how good Alonso was - and still is - that the success he did achieve doesn't live up to his potential.
Two world championships and sixth place in the all-time winners list is hardly a failure, in fact it makes him more successful than all but a handful of greats statistically, but everybody knows he should have had more. And Alonso knows what might have been... make that should have been.
Sebastian Vettel and Lewis Hamilton, who both made their debut grand prix appearances in the year following Alonso's day of days at Interlagos in 2006, have accumulated victories and titles in abundance over the past dozen seasons. Yes, Alonso has a Le Mans 24 Hours victory to his name, and a credible shot at becoming only the second driver to win the Triple Crown given how well he went in the Indianapolis 500 last year, but his grand prix legacy is not what it should have been.
Rather than being a Schumacher or an Ayrton Senna, a driver whose sheer weight of numbers guarantees him a place in the discussion of the all-time greats, he has become something else. The question 'where did it all go wrong?' will dog Alonso forever. Doubly so given his performance level on track during his years of underachievement never slid.
Emerson Fittipaldi is another driver who won two titles before settling into a long post-success coda to his F1 career with brother Wilson's team from 1976. All 14 of his wins, and 33 of his 35 podiums, were crammed into his first 70 starts, and he fed only on scraps in his final 74.
But Fittipaldi knew he was facing a big challenge with that move and went into it with his eyes open. Alonso has made most of his F1 career moves, starting with his ill-fated switch to the powerhouse McLaren team in 2007, with a view to taking titles.
And that is going to be Alonso's legacy, one of team changes that failed. When he signed for McLaren, a deal done at the end of 2005 and the season before his Renault contract came to an end, it was an obvious destination.
Like Schumacher a decade earlier, he'd realised that success for the Enstone-based team (previously Benetton) would likely be transient. He was right on that score, as the squad has only won four races since then, and in 2005 McLaren was the team that had produced the fastest car. And at that time it was the Mercedes works team.
Alonso's F1 legacy is going to be one of team changes that failed
But 2007 unravalled because of one unforeseen factor - the performance level of Hamilton. It's not stretching a point to argue that - because had McLaren instead opted to put a safe pair of hands in, for example Pedro de la Rosa, into the second car, then Alonso would have won the that crown.
The heavily-politicised season that did follow, one in which Alonso was a willing and active participant, forced Alonso to return to his old home at Renault. It was an 'any port in a storm' move that did yield a couple of wins in 2008 (one of them the Singapore Grand Prix that was later revealed to be the result of team-mate Nelson Piquet Jr crashing deliberately), but he knew his stock was high and the move he craved - to Ferrari - came to pass for '10.
And it was fine to tread water for a few years. After all, he was still young and there would be plenty more success to come.
There were two near misses during the Ferrari years. First, in 2010, when he lost out thanks to his team's strategic planning being focused entirely on nearest title rival Mark Webber's Red Bull in the title-deciding Abu Dhabi Grand Prix. When Webber, who was struggling in that race, pitted early to try to turn his night around, Alonso covered him.
But Vettel, 15 points behind going into the event, completed a dominant win and took the title, as Alonso spent the remainder of the race stuck behind Vitaly Petrov's Renault. Ferrari had made two errors - watching Webber too closely, and missing the fact that the tyres went through a graining phase during a stint that made it look like the performance was dropping away permanently. Head of race track engineering Chris Dyer ultimately paid the price for the strategic miscalculations...
But that was fine, he'd almost won in his first year with Ferrari. There would be other opportunities. Even after a difficult 2011, when Red Bull dominated, there was still plenty of time.
Then came Alonso's finest season, 2012, when he almost won the championship in a Ferrari car that started the season all over the place. He was unquestionably the driver of that year, but Vettel's miraculous revival after colliding with Bruno Senna on the first lap of the season-ending Brazilian Grand Prix denied him.
But that was still OK, for while time was passing Alonso was still in in his prime.
The 2013 Ferrari didn't work well, and after two early-season victories things started to get fraught inside the team. With new regulations coming for '14, there was still time for Alonso and Ferrari to turn the tables on Red Bull at least.
But, to the frustration of some inside the team, Ferrari chairman Luca di Montezemolo piled on the pressure during 2013 to keep improving that year's car. That led to the '14 chassis and engine package being neglected and Ferrari and Alonso didn't win a race in the first season of the new V6 turbo era.
As a result, Alonso lost patience with the Scuderia and then made one of his biggest mistakes: he underestimated new Ferrari chairman Sergio Marchionne's resolve to turn things around. He walked away to join McLaren-Honda for 2015.
But even then, it was OK. Because Honda was sure to make a success of its F1 comeback.
And so, Alonso repeated an earlier mistake of signing for McLaren and condemned himself to his current predicament.
For the past three-and-a-half seasons, Alonso has been left celebrating only minor points finishes. This has led to him seeking new challenges, such as his World Endurance Championship campaign with Toyota and contesting the 2017 Indianapolis 500.
Alonso has earned a reputation as a political troublemaker - but it would be unfair to characterise him simply as someone who makes trouble for its own sake
If Juan Manuel Fangio is, unduly, criticised for his tendency to join the best teams as he hopped from car to car in the 1950s (save, of course, for a move to Maserati in 1951 that almost killed him and coinciding with Alberto Ascari picking up two titles for Ferrari), Alonso is the antithesis - each car hop a frying pan/fire miss-step.
Amid all that, he has earned a reputation as a political troublemaker - as Christian Horner alluded to recently when he commented on the possibility of recruiting Alonso to replace Daniel Ricciardo at Red Bull. There's some truth to this, but it would be unfair to characterise Alonso simply as someone who makes trouble for its own sake.
Yes, he has a very clear idea of what needs to be done. Yes, he insists on a team being built around him. Yes, he demands his team-mate knows his place. Yes, once crossed he tends not to forgive and forget. Yes, he's single-minded and not afraid to say what he thinks - but that allows him to be a powerful driving force inside a team, even if it's not to the taste of all.
It's true he has also overstepped the line at times. When he left Renault for the second time, there were some in the team that were happy to see the back of him. During the good times, he's great, but during the bad times he can be hard work.
Alonso also guarantees his teams performance. While not the strongest qualifier - during his 2007 McLaren campaign the team reckoned he was a little slower than the stellar Hamilton on a qualifying lap - he is stunning for race performance.
In fact, his pace in races made him formidable. Alonso was also ruthless to a fault, an essential quality when it comes to winning world championships - and one that should have netted him more titles.
He is also a great calculator. When he won the 2008 Japanese Grand Prix for Renault after running second behind Robert Kubica's BMW in the early stages, he was able to call the strategy from behind the wheel. He knew what he needed to do to win, and what the team needed to do as well.
But Alonso has been less calculating when it comes to some of his team moves. Too often, he was in the right place at the wrong time, or turned his back on the wrong place just before it became the right one.
Alonso has one other great misfortunate: that he is competing in a time populated by many intense F1 talents. Even with Kubica knocked from the front rank of F1 drivers by his 2011 rallying accident, the top teams have been blessed with an embarrassment of riches with Hamilton, Vettel, Ricciardo, Max Verstappen and, at times, Kimi Raikkonen all on the market. With fewer standout drivers, teams would have been fighting over his signature every year.
Were Mercedes without Hamilton, or Red Bull without Verstappen, then both would seriously consider signing Alonso as their respective spearhead. But with such great talent available, they aren't willing to take the risk.
Could Alonso have done things differently? Certainly. Had he stayed with Ferrari, he would have had a shot at the title last year and potentially be leading the points race this year.
Had he not agitated against Hamilton at McLaren in 2007, maybe he'd have won that year's title. In retrospect, Alonso perhaps regrets the fact he didn't seem too disappointed at Interlagos not to win the crown that year - presumably because he was happy McLaren had lost out to Ferrari, which now looks pretty stupid.
No matter what the statistics say, Alonso is an F1 great right up there with the best of them
But back then, he had so much time. There would be many, many more opportunities...
But there were not. And in F1 there probably never will be again. His legacy will be some great wins, two quite brilliant championships and three world title near misses that mean, even with how much did ultimately go wrong, he was very close to being a five-time world champion today.
That is Alonso's F1 legacy. No matter what the statistics say, he's a great right up there with the best of them.
On October 22 2006, Fernando Alonso was on top of the world. He'd clinched a second consecutive world championship at the Brazilian Grand Prix, and with Michael Schumacher retiring it was legitimate to ask whether the Spaniard might go on eclipse his mark for grand prix victories and world titles. With 15 wins and 15 pole positions in his 86 starts, Alonso had the Formula 1 world at his feet.
Almost 12 years later, and he is stepping away from F1 having added 17 victories, seven poles and no more world championships in the subsequent 216 races. It's frankly pathetic that a driver of Alonso's prodigious ability has secured nearly as many seventh places (16) as wins during that time, and that's entirely down to the machinery that has been at his disposal.
Who knows whether Alonso will add to that record in F1, as for every Mika Hakkinen, who headed into a 'sabbatical' but never came back, there's a Nigel Mansell who does. But even if Alonso does return, his F1 legacy is likely to be of a talent wasted. It seems absurd to say that given what he did achieve, and it says much about how good Alonso was - and still is - that the success he did achieve doesn't live up to his potential.
Two world championships and sixth place in the all-time winners list is hardly a failure, in fact it makes him more successful than all but a handful of greats statistically, but everybody knows he should have had more. And Alonso knows what might have been... make that should have been.
Sebastian Vettel and Lewis Hamilton, who both made their debut grand prix appearances in the year following Alonso's day of days at Interlagos in 2006, have accumulated victories and titles in abundance over the past dozen seasons. Yes, Alonso has a Le Mans 24 Hours victory to his name, and a credible shot at becoming only the second driver to win the Triple Crown given how well he went in the Indianapolis 500 last year, but his grand prix legacy is not what it should have been.
Rather than being a Schumacher or an Ayrton Senna, a driver whose sheer weight of numbers guarantees him a place in the discussion of the all-time greats, he has become something else. The question 'where did it all go wrong?' will dog Alonso forever. Doubly so given his performance level on track during his years of underachievement never slid.
Emerson Fittipaldi is another driver who won two titles before settling into a long post-success coda to his F1 career with brother Wilson's team from 1976. All 14 of his wins, and 33 of his 35 podiums, were crammed into his first 70 starts, and he fed only on scraps in his final 74.
But Fittipaldi knew he was facing a big challenge with that move and went into it with his eyes open. Alonso has made most of his F1 career moves, starting with his ill-fated switch to the powerhouse McLaren team in 2007, with a view to taking titles.
And that is going to be Alonso's legacy, one of team changes that failed. When he signed for McLaren, a deal done at the end of 2005 and the season before his Renault contract came to an end, it was an obvious destination.
Like Schumacher a decade earlier, he'd realised that success for the Enstone-based team (previously Benetton) would likely be transient. He was right on that score, as the squad has only won four races since then, and in 2005 McLaren was the team that had produced the fastest car. And at that time it was the Mercedes works team.
Alonso's F1 legacy is going to be one of team changes that failed
But 2007 unravalled because of one unforeseen factor - the performance level of Hamilton. It's not stretching a point to argue that - because had McLaren instead opted to put a safe pair of hands in, for example Pedro de la Rosa, into the second car, then Alonso would have won the that crown.
The heavily-politicised season that did follow, one in which Alonso was a willing and active participant, forced Alonso to return to his old home at Renault. It was an 'any port in a storm' move that did yield a couple of wins in 2008 (one of them the Singapore Grand Prix that was later revealed to be the result of team-mate Nelson Piquet Jr crashing deliberately), but he knew his stock was high and the move he craved - to Ferrari - came to pass for '10.
And it was fine to tread water for a few years. After all, he was still young and there would be plenty more success to come.
There were two near misses during the Ferrari years. First, in 2010, when he lost out thanks to his team's strategic planning being focused entirely on nearest title rival Mark Webber's Red Bull in the title-deciding Abu Dhabi Grand Prix. When Webber, who was struggling in that race, pitted early to try to turn his night around, Alonso covered him.
But Vettel, 15 points behind going into the event, completed a dominant win and took the title, as Alonso spent the remainder of the race stuck behind Vitaly Petrov's Renault. Ferrari had made two errors - watching Webber too closely, and missing the fact that the tyres went through a graining phase during a stint that made it look like the performance was dropping away permanently. Head of race track engineering Chris Dyer ultimately paid the price for the strategic miscalculations...
But that was fine, he'd almost won in his first year with Ferrari. There would be other opportunities. Even after a difficult 2011, when Red Bull dominated, there was still plenty of time.
Then came Alonso's finest season, 2012, when he almost won the championship in a Ferrari car that started the season all over the place. He was unquestionably the driver of that year, but Vettel's miraculous revival after colliding with Bruno Senna on the first lap of the season-ending Brazilian Grand Prix denied him.
But that was still OK, for while time was passing Alonso was still in in his prime.
The 2013 Ferrari didn't work well, and after two early-season victories things started to get fraught inside the team. With new regulations coming for '14, there was still time for Alonso and Ferrari to turn the tables on Red Bull at least.
But, to the frustration of some inside the team, Ferrari chairman Luca di Montezemolo piled on the pressure during 2013 to keep improving that year's car. That led to the '14 chassis and engine package being neglected and Ferrari and Alonso didn't win a race in the first season of the new V6 turbo era.
As a result, Alonso lost patience with the Scuderia and then made one of his biggest mistakes: he underestimated new Ferrari chairman Sergio Marchionne's resolve to turn things around. He walked away to join McLaren-Honda for 2015.
But even then, it was OK. Because Honda was sure to make a success of its F1 comeback.
And so, Alonso repeated an earlier mistake of signing for McLaren and condemned himself to his current predicament.
For the past three-and-a-half seasons, Alonso has been left celebrating only minor points finishes. This has led to him seeking new challenges, such as his World Endurance Championship campaign with Toyota and contesting the 2017 Indianapolis 500.
Alonso has earned a reputation as a political troublemaker - but it would be unfair to characterise him simply as someone who makes trouble for its own sake
If Juan Manuel Fangio is, unduly, criticised for his tendency to join the best teams as he hopped from car to car in the 1950s (save, of course, for a move to Maserati in 1951 that almost killed him and coinciding with Alberto Ascari picking up two titles for Ferrari), Alonso is the antithesis - each car hop a frying pan/fire miss-step.
Amid all that, he has earned a reputation as a political troublemaker - as Christian Horner alluded to recently when he commented on the possibility of recruiting Alonso to replace Daniel Ricciardo at Red Bull. There's some truth to this, but it would be unfair to characterise Alonso simply as someone who makes trouble for its own sake.
Yes, he has a very clear idea of what needs to be done. Yes, he insists on a team being built around him. Yes, he demands his team-mate knows his place. Yes, once crossed he tends not to forgive and forget. Yes, he's single-minded and not afraid to say what he thinks - but that allows him to be a powerful driving force inside a team, even if it's not to the taste of all.
It's true he has also overstepped the line at times. When he left Renault for the second time, there were some in the team that were happy to see the back of him. During the good times, he's great, but during the bad times he can be hard work.
Alonso also guarantees his teams performance. While not the strongest qualifier - during his 2007 McLaren campaign the team reckoned he was a little slower than the stellar Hamilton on a qualifying lap - he is stunning for race performance.
In fact, his pace in races made him formidable. Alonso was also ruthless to a fault, an essential quality when it comes to winning world championships - and one that should have netted him more titles.
He is also a great calculator. When he won the 2008 Japanese Grand Prix for Renault after running second behind Robert Kubica's BMW in the early stages, he was able to call the strategy from behind the wheel. He knew what he needed to do to win, and what the team needed to do as well.
But Alonso has been less calculating when it comes to some of his team moves. Too often, he was in the right place at the wrong time, or turned his back on the wrong place just before it became the right one.
Alonso has one other great misfortunate: that he is competing in a time populated by many intense F1 talents. Even with Kubica knocked from the front rank of F1 drivers by his 2011 rallying accident, the top teams have been blessed with an embarrassment of riches with Hamilton, Vettel, Ricciardo, Max Verstappen and, at times, Kimi Raikkonen all on the market. With fewer standout drivers, teams would have been fighting over his signature every year.
Were Mercedes without Hamilton, or Red Bull without Verstappen, then both would seriously consider signing Alonso as their respective spearhead. But with such great talent available, they aren't willing to take the risk.
Could Alonso have done things differently? Certainly. Had he stayed with Ferrari, he would have had a shot at the title last year and potentially be leading the points race this year.
Had he not agitated against Hamilton at McLaren in 2007, maybe he'd have won that year's title. In retrospect, Alonso perhaps regrets the fact he didn't seem too disappointed at Interlagos not to win the crown that year - presumably because he was happy McLaren had lost out to Ferrari, which now looks pretty stupid.
No matter what the statistics say, Alonso is an F1 great right up there with the best of them
But back then, he had so much time. There would be many, many more opportunities...
But there were not. And in F1 there probably never will be again. His legacy will be some great wins, two quite brilliant championships and three world title near misses that mean, even with how much did ultimately go wrong, he was very close to being a five-time world champion today.
That is Alonso's F1 legacy. No matter what the statistics say, he's a great right up there with the best of them.