The tiny bronze coin, dating from the 1st-century AD, has what an author says is the only lifelike image ever made of Jesus.
Until now, the 24mm-wide coin was believed to show the face of King Manu who ruled the Mesopotamian kingdom of Edessa, in what is now southeastern Turkey.
But after nearly three decades of research, a leading biblical historian argues that Manu and Christ were one and the same person.
Ralph Ellis says his find is “one of the most important discoveries in modern history”.
He has studied the lives of the pair and cross-referenced all recorded and anecdotal evidence.
And he concludes that the striking similarities between them cannot be a coincidence.
Ellis says he is convinced “beyond any reasonable doubt” that the same man was posthumously referred to by two names - ‘King Izas Manu’, and ‘(King) Jesus Emmanuel’.
If he is correct, the coin’s image is the one and only accurate portrait of Christ.
Although Jesus is the most painted figure in all of western art, there is no physical description of him in the Bible.
The familiar image of him with long, flowing hair and white robe is said to be a later invention dating from the 6th-century AD.
Ellis’ findings are revealed in his book Jesus, King of Edessa, which is published in the UK this week.
The author, 59, admits his conclusions are controversial and contradict the conventional story of Christ.
He said: “Outside the Gospels there is precious little evidence attesting to the actual existence of the Christ figure.
“Though this might not be an issue for those who are satisfied on the basis of faith alone, which I understand and respect, as an historian this is deeply troubling.
“I have made it my life’s work to reconnect events and people from the Bible with known history.
“And Jesus - probably the most important figure in western history - deserves to be brought out from the biblical shadows and into the historical sunlight.
“The coin is the icing on the cake, and at last helps build up a strong case for the true identity and genealogy of the biblical Jesus.”
Many modern historians agree that Jesus the Nazarene - also known as ‘Jesus Emmanuel’ - actually existed and was executed by the Romans.
The Bible portrays him as a pacifist preacher in the Roman province of Judea, now part of Israel, who was called ‘Christ’ and ‘Messiah’ by followers, which translates as ‘anointed king’.
The scriptures say he was crucified by Pilate who feared that rising popular support for Jesus as a ‘King of the Jews’ could lead to the Jewish people revolting.
Ellis says his research suggests that Jesus was in fact a warrior king called ‘Izas Manu of Edessa and Adiabene’, also sometimes referred to as ‘Izates’ and ‘Monobazus II’, who also had his sights set on freeing Judea and its people from the Roman Empire.
He says his hypothesis explains every facet of the gospel narrative, including elements that have hitherto baffled traditional scholars.
Surviving accounts show that King Izas Manu and Jesus Emmanuel were both Nazarene Jews who lived in the City of Jerusalem in the first century.
And both were seen by the Romans as a threat because they aided the revolt of the Jewish people during the Great Jewish-Roman war of 66-73AD.
Although the historical records of Izas Manu’s death are inconclusive, Ellis believes he was among the three Jewish leaders who were rounded-up and crucified by the Romans, according to the 1st century Jewish historian Josephus Flavius.
This version of events has striking parallels with Jesus’ own death when he was led to the cross alongside two others, while wearing a crown of thorns and a purple cloak.
Ellis, who divides his time between the UK and France, said: “The traditional tiara of the Edessan monarchs was, as can be seen on the coins, a plaited crown of thorns.
“The fact that Jesus was the only convict said to have been forced to wear a crown of thorns as he was led to his execution, points to there being a link with this king.
“Jesus was also made to wear a purple cloak, which was a symbol of power and could only be worn by Roman emperors. To disobey was punishable by death.
“It is my theory that Jesus was forced to wear this crown in the biblical story because he, or more correctly King Izas Manu, had attempted to overthrow the Romans.
“Both the crown and cloak were overtly political statements, warning against further uprisings against Rome.”
Ellis has come under fire from what he calls “religious fundamentalists” since his book was first published in America in 2012.
Critics appear to have highlighted flaws in his theory and in particular some inconsistencies in the timelines between Jesus Emmanuel and Izas Manu’s lives.
Detractors pointed out that the Syrian coin, which says “King Manu” in Aramaic, was apparently minted for Manu VIII, who is known to have lived some 70 years after Izas Manu VI. But Ellis believes the coin is older.
Ellis added: “The connection between Jesus Emmanuel and King Izas Manu is a controversial one, to say the least, but the similarities are simply too great to be mere coincidence.
“Jesus is always portrayed as a pauper prince of peace, who was confusingly involved in an unknown revolution in the AD30s.
“My research shifts him in the historical timeline from the AD30s to the AD60s and makes him a key figure in the Great Jewish-Roman War.
“It is my theory that he was, in fact, a warrior king who challenged the might of the Roman Empire in AD68 and paid the price.
“Anything that contradicts the orthodox story of Jesus, which has become central to the church for over 1,500 years, is likely to attract a lot of criticism.
“But when viewed from a historical perspective the case is very strong for Jesus Emmanuel and Izas Manu being one and the same.”
For more information on Jesus, King of Edessa visit www.edfu-books.uk.