The item in question is the famous and unique napkin on which the first promise of a contract was written to secure the 13-year-old Lionel Messi for FC Barcelona.

It changed the fortunes of both the club and Messi himself who went on to become one of the greatest players of all time. The original napkin in blue ink is being offered at Bonhams on behalf of Argentine agent, Horacio Gaggioli, in an online auction running from 18 to 27 March.

The commitment-to-a-contract-on-the-napkin was written in blue ballpoint pen by Carles Rexach, Barcelona’s sporting director.

It stated: “En Barcelona, a 14 de diciembre del 2000 y en presencia de los Sres. Minguella y Horacio, Carles Rexach, secretario técnico del FC Barcelona, se compromete bajo su responsabilidad y a pesar de algunas opiniones en contra a fichar al jugador Lionel Messi siempre y cuando nos mantengamos en las cantidades acordadas”.

(“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 statement is signed by Carles Rexach, a longstanding player and coach for the club and Josep Minguella, the transfer advisor to the club who, together with Rexach, arranged for Messi’s tryout in September 2000. Horacio Gaggioli, the Argentine agent who brought Messi to the attention of Carles Rexach, was also at the table and signed the napkin.

It was an unorthodox way to confirm interest in one of the most exciting young players in the world, but the recruitment of Messi had not been without its obstacles – his height being one issue, the amount of money to be expended on a 13-year-old was another.

Born in 1987 in Rosario, Argentina, Lionel Messi came from a humble background – his father, Jorge, was a supervisor in a steel mill, his mother Celia also worked in a factory. However, the prodigious talents of Messi soon became evident and he had been scouted by FC Barcelona while playing for his local club, Newell’s Old Boys, at the age of 12. Messi and his father, Jorge, were flown to Barcelona for a try-out, but negotiations stalled. Some members of the club’s hierarchy were not convinced Messi was worth the investment – for one thing, he was under five feet tall.

By December 2000, Jorge Messi had become impatient at the lack of commitment from the club. He was waiting to get a final decision from FC Barcelona. On 14 December, Rexach, Minguella and Gaggioli met for lunch at the Pompeia tennis club. Rexach, sensing that things had reached a crucial moment, pulled a paper napkin from a dispenser on the table and began to write.

The napkin – measuring a mere 16.5 x 16.5cm – did the trick. That night, the president of FC Barcelona, Joan Gaspart, finally confirmed the agreement, this time on more substantial paper. The rest is history. With Lionel Messi as its Number 10, FC Barcelona had years of unprecedented success.

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.

“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.”