Cristiano Ronaldo and Lionel Messi are two of the greatest footballers of all time.
The pair have rewritten the history books over the course of their glittering careers, scoring goals with amazing speed and winning 11 Ballon d'Or awards within them.
Their sporting rivalry has defined a generation, so much so that pretty much every other player - past or present - has been asked to pick their favourite of the two global icons.
However, it all could have been so different, because Barcelona had the chance to make Ronaldo and Messi teammates back in 2003.
Had they done so, the footballing world in the present day would almost certainly look very different.
So why did Barca pull out of the deal, especially when they were quoted a transfer fee for Ronaldo that was €2m less than what Manchester United ended up paying?
Because of Ronaldinho. The Blaugrana believed they didn't need to add another winger to their squad due to the impending arrival of the Brazilian from Paris Saint-Germain.
That's according to former Barca president, Joan Laporta, the man who is currently the favourite to be re-elected during this month's presidential election.
Laporta said in a chat with Twitter account, Iniestazo, per Sports Central: "We were about to sign Ronaldinho and Rafa Marquez. "Marquez's people proposed Cristiano Ronaldo to us. He was at Sporting Clube at the time. One of his agents said that they had a player who they had sold to [Manchester] United for 19 million, but they'd sell him to us for 17 million.
He added: "But we had already invested in Ronaldinho at the time. Cristiano played more out wide than in the centre. We thought we were covered, so we rejected him and I don't regret it.
Wow. Ronaldo and Messi in the same team? The stuff of hypothetical dreams.
However, had Ronaldo been signed at the same time as Ronaldinho, Messi would probably have struggled to break into the first-team like he did in 2004.
In hindsight, maybe Barca's decision to reject Ronaldo was best for both players....