Having come close to leaving Barcelona in 2020, Lionel Messi and the Liga giants are set to finally go their separate ways, with the club unable to hold on to their prize asset.
New club president Joan Laporta had consistently sounded positive signals to the Barca faithful regarding Messi's contract negotiations as they hammered out extension details, but it will not happen now.
The news has been greeted with disbelief across the world and Barca supporters are angry that the club has lost the player considered by many to be the best to ever play for them.
What happened in the course of the negotiations to prevent Messi from staying at Barcelona? Goal takes a look.
Why has Lionel Messi left Barcelona?
Barcelona explained that "financial and structural obstacles" are the reason why they could not close a new contract with Lionel Messi, thus paving the way for his departure.
The "obstacles" referenced by the Catalan club are La Liga's Financial Fair Play regulations and in particular the competition's salary cap rules.
Barca's financial situation, which sees the club with debts over €1 billion, is a major contributing factor in the scenario. Losses of nearly €600 million mean that Barcelona must vastly reduce their wage bill in order to comply with La Liga's Fair Play restrictions.
However, they have not been able to do that while facilitating a deal for Messi and president Laporta indicated that the long-term sustainability of Barcelona is "above everything else - even the best player in the world."
He explained: "The salary mass is 110 per cent of the total income of the club, we don't have any margin in terms of salary.
"The rules and regulations of the Spanish La Liga is regulated by Financial Fair Play and we don't have any margin.
"We knew that when we got to the club, but the numbers that have been presented to us, they are a lot worse than were exposed initially and those that we were working with. That means that the losses are more than we had expected.
"What we are spending is a lot more than we expected and the current contracts mean that we have this salary mass of great magnitude.
"This is all tied to fair play. La Liga doesn't follow the criteria of cash, that is why we couldn't fit in the first contract that we agreed with Leo Messi.
"In order to meet fair play, Barca had to agree to an operation that would impact the club for the next 50 years in terms of television rights. That means that we can't make a decision that impacts the club for the next 50 years.
"The club is more than 100 years old and is above everything - even the best player in the world. We will always thank him for everything he has done for us. The club goes above players, the president.
"We wanted to take the risks. We have realised what the real situation is at the club and we would have put the club at great risk.
"The salary mass has a great deal to do with that after a calamitous situation that was down to the previous board. If we terminate current contracts, that also has risks. We can't destroy the club."
What does Lionel Messi's departure mean for Barcelona?
Barcelona will now have to properly figure out a post-Lionel Messi future, having planned the next few years with their talisman in the team. As Laporta said: "A new era starts now. There will be a before and after Leo, as there was with other great players."
Having benefited from the influential presence of the six-time Ballon d'Or winner for 17 seasons, they will attempt to replace him. However, it is highly unlikely that there will be another marquee signing.
Players such as Antoine Griezmann and new addition Memphis Depay will be expected to shoulder the burden, while a lot of hope will be placed in young stars such as Ansu Fati and Pedri to plug the gap.
There will potentially be major financial tremors for Barcelona as a result of the abrupt exit too, with the club now facing into a future where they cannot trade with potential sponsors using the unique appeal of Messi.
Did Lionel Messi want to stay at Barcelona?
Messi was keen to remain at Barcelona and, according to Laporta, he attempted to "make it easy" to get a deal done so that he could stay.
"We have been at it for two months and we have gone through different stages. The first agreement was two years to be paid in five, and Leo agreed with that," said the Barca president.
“He was always present in negotiations and he tried to make it easy for us.
“When we thought that would be allowed in Financial Fair Play, the criteria of cash came into play, and it is not allowed here like other countries.
"Then we agreed to a five-year contract, which was also accepted by Leo. We all agreed."
It is true that Messi was ready to leave Camp Nou in August 2020, but the Argentina star was subsequently won over by the new regime and, while his contract expired, he was set to sign a new five-year contract.
Where next for Lionel Messi?
Messi's future is now up in the air, but when it comes to potential destinations, only a small number of clubs could afford his wages.
Paris Saint-Germain are widely understood to be the best-placed club to sign Messi thanks to their financial might and such a move would see the Argentine reunite with former Barca team-mate Neymar.
He has long been linked with a move to Manchester City, fuelled in part by the fact that it would mean a reunion with Pep Guardiola.
"He will wear the No.10 because we were convinced with Grealish," said the Catalan. "And we were convinced Leo would continue at Barcelona, so right now he is not in our thoughts."
Other clubs who could possibly boast enough finance to lure Messi are Manchester United, though the Red Devils just forked out for Jadon Sancho, and Inter, who would probably have to sell Romelu Lukaku.