Lewis Hamilton matched Michael Schumacher's record of seven world titles at Sunday's Turkish Grand Prix, putting the two drivers on an equal standing in Formula One's record books.
The argument over who is the greatest of all time (or GOAT) is entirely subjective and has no single satisfactory answer, but at a point where so many of the two drivers' statistics match up, this seemed like as appropriate a time as any to address the question.
So let's start with those mind-blowing stats before moving on to some of the more controversial and debatable categories of greatness....
The statistics
Although they are tied on titles, Hamilton now leads Schumacher on the two big records used to measure speed and success in F1: pole positions and wins.
There are some categories where Schumacher still holds the edge -- fastest laps, most wins in a season, successive wins -- but the outright record on two of those three has been matched or surpassed by Sebastian Vettel. Schumacher's "second career" at Mercedes between 2010 and 2012 skews his percentage stats unfavourably as he scored only one podium in that period compared with the 154 he scored between 1994 and 2006.
Of course, Hamilton is still active in F1, so his percentage stats could go either way, but the safe money is on him bolstering those numbers and extending his advantage over Schumacher by the time he retires.
Titles
Hamilton 7 - 7 Schumacher
Wins
Hamilton 94 - 91 Schumacher
Career starts
Hamilton 264 - 306 Schumacher
Pole positions
Hamilton 97 - 68 Schumacher
Points finishes
Hamilton 227 - 221 Schumacher
Podiums
Hamilton 163 - 155 Schumacher
Fastest laps
Hamilton 53 - 77 Schumacher
Races until first pole
Hamilton 5 - 41 Schumacher
Races until first win
Hamilton 6 - 18 Schumacher
Most wins in a season
Hamilton 11 - 13 Schumacher
Successive wins
Hamilton 5 - 7 Schumacher
Successive podiums
Hamilton 16 - 19 Schumacher
It's interesting, but perhaps nothing more than a coincidence, that despite two very different journeys in F1, they both secured their seventh title at the age of 35. If we cap their careers at that age, then the percentage win stats are very slightly in favour of Schumacher over Hamilton.
Age at first title
Hamilton 23 - 25 Schumacher
Age at second title
Hamilton 29 - 26 Schumacher
Age at third title
Hamilton 30 - 31 Schumacher
Age at fourth title
Hamilton 32 - 32 Schumacher
Age at fifth title
Hamilton 33 - 33 Schumacher
Age at sixth title
Hamilton 34 - 34 Schumacher
Age at seventh title
Hamilton 35 - 35 Schumacher
The stats can be used to make arguments for either driver, but considering Hamilton now holds the race win record and is likely to extend the championship record in the coming years, it's likely to only become harder and harder to make the numbers stack up in favour of Schumacher.
Verdict: Hamilton
Pure speed
This is always going to be a controversial topic and is among the hardest to draw a conclusion from. Statistically speaking, Hamilton has the record for pole positions but Schumacher has the record for fastest laps -- although both of those stats are easy to argue into irrelevance.
Pole positions count for nothing in terms of points, so it's possible one-lap pace can be sacrificed for race pace to achieve victory (especially as drivers had to qualify with their race fuel for a part of Schumacher's career). What's more, if you have the fastest car on the grid, then a large part of the job is done, and arguably Schumacher had more "relatively slow" cars in his career than Hamilton.
As for fastest laps, they have carried a point only since the start of last year, so a fastest lap has been of little relevance (other than bragging rights) for the majority of both drivers' careers. It's also often the case that a fastest lap has been secured by a driver being on fresh tyres and low fuel at an opportune time of the race, which is often a by-product of a specific strategy rather than a true indicator of a driver's race pace.
Moving away from the stats, both drivers have been heralded for how they control a car on the limit, but then there are questions as to whether the likes of Gilles Villeneuve and Ayrton Senna would have left both Schumacher and Hamilton in their wake if it came down to a low-fuel, fresh-tyre run in equal machinery. It's a question that we will never be able to answer.
Nevertheless, a recent study by F1 partner AWS aimed to answer it anyway by creating a complex matrix of comparisons between teammates. Senna came out on top, 0.114s ahead of Schumacher on an imaginary lap, who in turn was 0.161s faster than Hamilton. But the study was somewhat discredited by its questionable methodology and the fact Heikki Kovalainen and Jarno Trulli made surprise appearances in the top 10.
The comparison between Hamilton and Schumacher is made even harder by the two eras the drivers raced in. Lots of tales of Schumacher's heroics come from behind the cockpit of a Benetton in the early 1990s, which was a very different beast to the aero-sensitive and far heavier cars of today.
But if looking for differences proves futile, finding similarities can at least give us an indication as to why both drivers have been so successful. Mercedes' trackside engineering director Andrew Shovlin has worked with both drivers (Schumacher between 2010 and 2012 and Hamilton from 2013 to now) and believes both had very similar traits.
"The two characters couldn't be more different, but if you look at how they drive, there are similarities," he said earlier this year. "When Michael arrived at our team, the thing that stood out with him was the way he would always go after marginal gains, and it didn't matter if it was 0.01s, he would try to get it and he would collect those up.
"Michael also had an ability to drive whatever [car] balance was quickest. If it was an understeering car, he would do it. If he needed to move the work onto the front tyres, he could. And so he was very adaptable in his driving style.
"Those are two characteristics that Lewis very much has. A lot of the good drivers don't have any particular style, it's just whatever they need to adapt to, they will do it.
"It didn't matter how many things you told Michael to do on a lap, he would do them. Whether it was moving brake bias to look after tyres or whatever he needed to do to get them in the right window, he would do it.
"Again that's one trait that Lewis has; you can just keep layering one thing on top of another and he doesn't forget it, and then you can give him more things to do and he just adds it on top.
"So the way they are in the car, they are actually more similar than you might think. It's just out of the car they are two quite different people."
But pure speed is almost a given among drivers in F1's GOAT debate and it is the other attributes that might help tip the balance in favour of one driver over the other.
Verdict: Too close to call
Work ethic
Based on the characterisation of the two drivers in the media, this category goes comfortably to Schumacher. But dig a bit deeper into their careers and it's a much closer battle than you might think.
The Schumacher story is well known: he was key to the rebuilding of Ferrari between 1996 and 2000, bringing technical staff such as Ross Brawn and Rory Byrne from Benetton while contributing to a winning atmosphere that ultimately led to the domination of the sport. It's wrong to suggest it was all down to Schumacher -- it was very much a team effort led by team principal Jean Todt -- but the success of Schumacher and Ferrari during that era is inseparable.
Schumacher's work ethic while at Maranello remains legendary. There are stories of how he would talk with engineers on the phone about a new part on a Tuesday and be in the car testing it by Wednesday. And it was his desire to improve by testing that sets him apart from any other driver of his era.
In his most successful period, between 2000 and 2006, Schumacher completed 89,533 test kilometres in a Ferrari -- the equivalent of circumnavigating the earth twice. Those kilometres were spread over 279 days of testing in total, meaning that in the space of seven years he spent a total of nine months solid testing, with race weekends on top!
By contrast, Hamilton joined Mercedes in 2013 at a point when the majority of the building blocks for domination had already been put in place. The move from McLaren to Mercedes at the end of 2012 was unquestionably a great career move, but -- so the argument goes -- he was not directly responsible for the hard yards that led to the team's domination from 2014 onwards.
But that argument does a huge disservice to Hamilton's role since 2013 and the level of hard work required to keep Mercedes at the top for the following seven seasons. Hamilton might shun the idea of testing away from preseason (and regulations have significantly limited the amount of track time since Schumacher's era), but it's wrong to assume he clocks off the minute he leaves the circuit.
"Lewis' rivals might like to think he is just fast in the car but doesn't put the hours in, but he's actually one of the hardest-working guys we've ever known," Shovlin says. "The more he understands about tyres, about how the car works and how to use all the available tools, the more he is able to take that information and build it into his driving.
"It's just the relentless way he looks at every missed opportunity as something that needs fixing before the next race and he goes off and works on it with Bono [his race engineer, Peter Bonnington], Marcus [Dudley, Hamilton's performance engineer] and the wider engineering team trying to understand any issues.
"It's just the way he is constantly building his skill set, and he's so long into a career that you might think a driver would top out their skill set, but Lewis keeps finding new and different things to do to get the best out of the car and the tyres."
As a result, this category is much closer than it might seem at first glance, but Schumacher's sheer dedication and sacrifice of time over the years at Ferrari mean he edges it.
Verdict: Schumacher
Racecraft and race strategy
The ability of both drivers to take a race strategy and make it play out successfully on track is key to their success. But the type of driving required in Schumacher's era is almost completely at odds with Hamilton's today.
Schumacher was famous for his ability to make a strategy work by driving a series of "qualifying laps" to make the difference on a key stint between pit stops. Such turns of pace were often the key to success in his Ferrari days and were masterminded by Brawn on the pit wall.
By contrast, Hamilton's recent success lies in his innate ability to manage his tyres and tailor his driving and his pace to the conditions to make the rubber last. At races this year, we have seen Hamilton dictate the strategy from the cockpit, sometimes overruling the pit wall based on what he is feeling from each corner of his car.
Schumacher never really got to grips with the "Pirelli era" of tyre management in F1 and was much more successful on Bridgestone tyres that were tailor-made for his Ferrari and capable of being pushed to the limit lap after lap. Both types of driving require exceptional skill, and both Schumacher and Hamilton are arguably the best of their generation at their given style. But given those differences in race management, it seems unfair to make a direct comparison.
Verdict: Comparison not valid
Rivalries
The achievements of both Schumacher and Hamilton have always had to contest with the argument that they win only because they have had the best car. Leaving to one side the counter-argument that they are in the best car (or have helped develop the best car) for a reason, it's also fair to say you can only beat the teams and drivers you are racing against. As a result, their greatness is partly defined by the rivalries they've had.
Schumacher won titles in dominant cars against lesser opposition, but the career of his greatest rival was tragically cut short in 1994. Had Senna not died at the 1994 San Marino Grand Prix, there is a strong argument he would have beaten Schumacher to that year's title, which ultimately saw Schumacher win by a single point over Senna's teammate at Williams, Damon Hill.
On winning his first title in 1994, Schumacher dedicated the victory to Senna: "For me it was always clear that I wasn't going to win the championship and Ayrton was going to win the championship, but he hasn't been there for the last races, and I'd like to take this championship and give it to him. He is the driver who should have earned it because he had the best car and was the best driver. That's my feelings about him."
That's not to play down Schumacher's achievement against his later rivals such as Hill, Jacques Villeneuve, Mika Hakkinen and Fernando Alonso, but the extent to which Senna would have dominated the 1990s had he survived Imola 1994 remains one of F1's most tragic and compelling what-ifs.
Hamilton's era of success has seen some overlap with Schumacher's in terms of rivals, such as Alonso, but he has arguably gone up against a stronger range of competitors in Kimi Raikkonen (in his 2007 title year), Sebastian Vettel, Nico Rosberg and Max Verstappen. What's more, he has won a race in every season of his career, despite having subpar cars in 2009 and 2013.
But it's the direct comparison with teammates that really gives Hamilton the edge over Schumacher in this category. Schumacher had a world champion as a teammate only once -- in 1991 during his six races alongside Nelson Piquet at Benetton -- whereas Hamilton has gone head-to-head with Alonso, Jenson Button and Rosberg.
True, he tied on points with Alonso in 2007, but he was a rookie and Alonso was the reigning two-time world champion (plus Hamilton technically won the battle on countback of individual results). Button beat him in the driver standings in 2011, but Hamilton came out on top in 2010 and 2012. In a close title battle, Rosberg beat him in 2016, but again, Hamilton finished all the other seasons they had as teammates ahead and two of them with titles.
The deciding factor in this comparison is that Schumacher held No. 1 status at Ferrari, with Eddie Irvine, Rubens Barrichello and Felipe Massa all contracted as the No. 2 driver alongside him. During his time in F1, Hamilton has never requested No. 1 status and has been granted it only when a championship is on the line and his teammate is already out of contention.
Verdict: Hamilton
Sportsmanship
It's essential to have a winning mentality in F1, but there's a difference between a winning mentality and a win-at-all-costs mentality.
Schumacher's F1 career will forever be tarnished by the events at the 1994 Australian Grand Prix, the 1997 European Grand Prix and qualifying for the 2006 Monaco Grand Prix. In each he exhibited a desire to win that went to the very limit (or beyond), and in two of the three cases his actions were punished by the FIA.
His collision with Hill at the final race of the season in 1994 secured him his first title just moments after it appeared to be slipping through his fingers after he made a mistake and hit the wall. Although he wasn't penalised for it, he appeared to force a collision as Hill attempted to overtake, and the damage to Hill's Williams ensured neither scored points, giving Schumacher the title.
A similar move on Jacques Villeneuve at the final race of the season in 1997 failed to pay off and resulted in Schumacher being excluded from the championship after an FIA investigation. Both of those incidents could be marked down to his relatively young age (he was 28 in 1997), but the Monaco incident, where he crashed on purpose at the Rascasse corner in order to prevent drivers behind him from beating his qualifying lap time, came at the age of 37 and when he was already a seven-time world champion.
Such incidents gave Schumacher a reputation for ruthlessness and remain divisive among F1 fans to this day. But it should be noted that those who worked with Schumacher tell a different story of his true character away from the track.
"He was a pretty misunderstood character," Brawn told Sky Sports in the docuseries Race to Perfection. "I don't know if in his own mind he quite enjoyed the sort of impression he created because he was quite an intimidating character in many ways.
"But if you knew him personally, he was quite the opposite, very engaging, very personal. So many times I introduced him to people who, before they met him, thought he was a despicable, horrible character, and you introduce them, and once they got to know him, they completely changed.
"I had that happen so many times because there was Michael the racing driver out on the track and there was Michael the human being away from the track. "I don't know of anyone who worked with Michael who had a bad word to say about him. Lots of people who raced against him had a different opinion, but nobody I know who ever worked with Michael ever had a bad opinion about him because of his integrity, his commitment, his human side.
"He was a very strong team member of any team he was part of, and it's a tragedy what's happened, but he's a lovely human being."
Hamilton has often found himself on the wrong side of decisions from the FIA stewards, but it has usually been for honest mistakes.
His most questionable moment came in 2009 when he was disqualified from the Australian Grand Prix for "misleading" the stewards in an investigation over why he overtook Trulli under yellow flags. It later emerged his testimony to the stewards was a result of orders from McLaren sporting director Dave Ryan, and at 24 years old it was perhaps understandable that he went along with it.
But Hamilton has matured a lot since then. At last year's Brazilian Grand Prix, he took the blame immediately after a collision with Alex Albon, making the stewards' decision to strip him of his podium finish straightforward.
Hamilton's enormous self-belief means he has only ever asked for a straight fight in equal machinery with his teammate, and that makes his achievements all the more impressive.
Verdict: Hamilton
Legacy
This is arguably the most important category when it comes to "greatness" but also the hardest to judge (not least because Hamilton has yet to finish his career).
It is also incredibly subjective, with no numerical measurement and strong arguments for each driver -- as well as the argument that the premise of such a comparison is fatuous in itself. Nevertheless, it is possible to look at what the two drivers have achieved and what impact they have had on the world outside F1.
During his career, Schumacher raised the bar in terms of professionalism in Formula One. Travel around the world and you'll spot replica Schumacher helmets on motorcycle riders in major cities, while his name remains synonymous with the sport in every corner of the globe. At a time when F1 was at its prime in terms of audience and relevance, Schumacher was its most recognisable figure, and his story remains inspirational to millions of people.
He conducted the majority of his charitable work in private, but examples of his generosity occasionally made the headlines, such as his $10m donation to victims of a tsunami in Asia in 2005. Competing in an era before social media, he guarded his private life from the media, but his on-track achievements were still enough to mark him out as one of the greatest sporting icons of all time.
Ever since Schumacher suffered serious head injuries in a skiing accident in 2013, his family have guarded his privacy further, but the Keep Fighting Foundation set up in his name continues to work with projects in culture, education, science and public health.
In comparison to Schumacher, Hamilton's private life has been an open book during his time in F1. Traditional media have built him up and torn him down several times over, but the character that has emerged is one of the strongest and most relevant in the sport's history.
Through social media, he has aimed to tell his story and has increasingly tailored his messages to inspire others rather than self-promote. This year he has used his platform to fight against racial injustice, push for greater diversity in motorsport and continue to highlight the dangers of climate change -- three issues that he has led the conversation on within his sport.
His voice is one of the very few in the paddock that transcends the F1 bubble, and he is continuing to use it to spread a positive message around the world.
Verdict: Impossible to compare
So... who's the GOAT?
The chances are you had your mind made up before you opened this article, and it's unlikely any of the arguments above have changed it.
Schumacher fans will never be convinced Hamilton is greater, while Hamilton fans will never accept Schumacher as the undisputed GOAT. Equally there are numerous other drivers from F1's history who should be added to the debate and have received only a passing mention (or no mention at all) in this article.
But on the off chance you're still undecided, take a look back through the categories and decide which ones you value the most in a F1 driver. That should give you your answer ...