It's very common for boxers, journalists and fans to name Muhammad Ali as the greatest fighter the sport has ever seen.
The American legend is possibly the biggest sporting icon of all time and his fights with the likes of Joe Frazier, Sonny Liston and George Foreman were epic.
Ali was the face of the sport during the 1960s and 1970s, so much so that his reputation is as prominent as ever in the present day.
Of course, there are a few other names that are always mentioned when asked to name the greatest boxer of all time. Mike Tyson, Joe Louis, Ray Leonard, Ray Robinson and Rocky Marciano to name a few.
There's also Floyd Mayweather, a man who boasts the impeccable and frankly ridiculous record of 50-0-0.
He's without doubt one of the greatest to have laced a pair of gloves on the professional circuit and he's also one for believing in his own hype.
Back in 2017, when he was 49-0-0, Mayweather was a guest on ESPN and was fuming when he heard that hosts David Lloyd and Carl Champion had named Ali ahead of him as the greatest boxer ever.
"What are we judging fighters on?" he asked in response to the rankings, with both Lloyd and Champion placing him fourth.
"Because if we're judging fighters on standing for a cause, then it's Ali hands down. But if we're talking about taking the least punishment and breaking records, it's Floyd Mayweather.
"Muhammad Ali paved the way for me to be where I'm at today, he's a legend. But when we talk about record breaking, we've got to talk about Ali losing his world title to a fighter with only seven fights.
"I have to take my hat off to Ali, but I didn't give this sport 40 years to say that there's another fighter better than me."
Lloyd then argues that Ali's bouts against the likes of Frazier, Liston and Foreman are the reason why he's number one, stating that Mayweather hasn't been involved in fights of the same calibre.
The Money Man hits back by saying: "That's not cool. That is not cool.
"What I'm here to teach fighters is this: The name of the game is to hit and not get hit. It's not about taking punishment.
"And I love Ali, but sitting on the ropes, taking punishment as far as doing a rope-a-dope - that's not cool."
Does Mayweather have a point? After all, this is a guy who's schooled Oscar De La Hoya, Canelo Alvarez, Manny Pacquiao and many more world-class fighters.
At the end of the day, picking between a pair like Ali an Mayweather is nigh on impossible.
They're completely different fighters from separate eras, so maybe it's best to just say 'two of the greatest of all time', eh?