The tiny bronze coin, dating from the 1st-century AD, has what author Ralph Ellis 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, the leading biblical historian argues that Manu and Christ were one and the same person.
Ralph Ellis describes 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.
Elllis’ 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.
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.
Ellis, who divides his time between the UK and France, added: “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.”
Critics of his theory have highlighted inconsistencies in the timelines between Jesus Emmanuel and Izas Manu’s lives.
Top pic: SWNS