A napkin that helped launch the career of football superstar Lionel Messi, is being put up for auction.

The napkin, itself something of a legend in the world of football, served as an unusual contract to secure the Argentine prodigy's move to Barcelona in 2000. Potential bidders will face a starting price of £300,000 for the piece of football history and have until 17 May to make an online offer with auctioneers Bonhams.

Messi, then 13, had been on trial with Barcelona in September of that year, but by December his father Jorge had reportedly become frustrated by the club's failure to tie down his son. The LaLiga club's sporting director Carles Rexach stepped in, pulling out a 16.5cm by 16.5cm napkin at the Pompeia tennis club in the company of Josep Minguella, transfer adviser to the club, and Horacio Gaggioli, the Argentine agent who brought Messi to their attention.

The text of impromptu deal, reads: "In Barcelona, on 14 December 2000 and the presence of Messrs Minguella and Horacio, Carles Rexach, FC Barcelona's sporting director, hereby agrees, under his responsibility and regardless of any dissenting opinions, to sign the player Lionel Messi, provided that we keep to the amounts agreed upon." The napkin was signed by Rexach, Minguella and Gaggioli. That night, Barcelona president Joan Gaspart confirmed the agreement.

It is being sold on behalf of Gaggioli, who brought Messi to the club's attention. Messi went on to score 672 goals for the club, winning four Champions League titles and 10 LaLiga titles.

Ian Ehling, head of fine books and manuscripts at Bonhams New York, said: "This is one of the most thrilling items I have ever handled. "Yes, it's a paper napkin, but it's the famous napkin that was at the inception of Lionel Messi's career.

Read more:Maradona's mysteriously lost trophy reappearsCricket star quits political party after a week'Brave' police investigate crocodile sighting "It changed the life of Messi, the future of FC Barcelona, and was instrumental in giving some of the most glorious moments of football to billions of fans around the globe." Messi, who currently plays for Inter Miami in the MLS, has eight Ballon d'Or awards to his name, and won the World Cup with Argentina in 2022. He is considered by many to be the greatest player of all time..