Gaius Appuleius Diocles would have earned, in today's money, £15 billion from his professional earnings.
It comes as no surprise to sports fans nowadays that athletes earn massive amounts of money each year.
Whether in the form of salaries or sponsorship contracts or a combination of both, some top football stars amass staggering fortunes.
Figures like Cristiano Ronaldo, Lionel Messi, and Kylian Mbappe have appeared on Forbes' list of the highest-paid athletes.
But all their earnings pale in comparison to one particular individual, an ancient Roman chariot racer who would have earned £15 billion from his professional earnings, according to researchers.
Who is Gaius Apollonius Diocles?
According to the Daily Mail, experts have uncovered details about Gaius Apollonius Diocles, who rose from humble beginnings as a slave to become a champion charioteer in second-century Rome.
The newspaper notes that Gaius Apollonius Diocles' earnings surpass even the highest-earning athletes, with Cristiano Ronaldo earning a mere £112 million annually.
Despite his move to Saudi Arabia last January, the majority of the Portuguese star's wealth came from off-field sponsorships.
Lionel Messi, who plays for Inter Miami, came in second on the list of highest earners with £107 million earned last year, divided between on-field and off-field earnings.
Gaius Apollonius Diocles would have earned £15 billion from his professional earnings.
Taking the third spot is Kylian Mbappe, who, after signing a massive new contract with Paris Saint-Germain two years ago, became the highest-paid player, earning £82 million on the field but a relatively low £16 million off the field.
In comparison, the incredibly powerful charioteer earned 35,863,120 sesterces (an ancient Roman currency) in prize money during his professional career, which is equivalent to £625 million annually in today's terms, according to the Daily Mail.
The newspaper quotes historian Peter Strack from the University of Pennsylvania revealing the inscriptions made by his fellow charioteers on a memorial monument in Rome earlier this year.
Gaius Apollonius Diocles would earn £625 million annually in today's terms.
The tribute to Gaius Apollonius Diocles upon his retirement in 146 AD reads: '42 years, 7 months, and 23 days,' the champion of all charioteers.
Professor Strack, an associate professor of classical studies, said, 'The modern sporting spectacles that we manage to put on—and sometimes recoil at—are diminished in comparison to the popular entertainments of Rome.'
And he added, 'The Circus Maximus, the pulsating heart in the center of the empire, accommodated a quarter million people for weekly chariot races.'
He explained, 'The drivers were chosen from the lower classes of society, belonging to teams supported by large companies that heavily invested in horse training and equipment maintenance.'
The Circus Maximus accommodated a quarter million people.
As was the case in modern times, ancient athletes also attracted the attention of sponsors, and Gaius Apollonius Diocles had companies vying to associate with him. This led to millions being added to his bank account during his professional career.'
He concluded, 'The highest-paid athlete among them was Spanish, Gaius Apollonius Diocles from Lusitania (a Roman province in the western Iberian Peninsula). He spent short periods with the Whites and the Greens before settling on a long journey with the Reds.'
Gaius Appuleius Diocles : Greatest chariot racer of all time
Professor Strack added, '24 years of gains brought Diocles - likely an illiterate man whose distinctive move was the powerful final sprint - an astonishing sum of 35,863,120 sesterces.'
This number was recorded on a massive inscription erected by his fellow chariot drivers and admirers in Rome in the year 146, which highly praised him upon his retirement.