There have been plenty of attacks on Christianity over the years, but few claims have been more surprising than one advanced by an obscure Swedish scholar this spring.
The Gospels do not say Jesus was crucified, Gunnar Samuelsson says.
In fact, he argues, in the original Greek, the ancient texts reveal only that Jesus carried "some kind of torture or execution device" to a hill where "he was suspended" and died, says Samuelsson, who is an evangelical pastor as well as a New Testament scholar.
"When we say crucifixion, we think about Mel Gibson's 'Passion.' We think about a church, nails, the crown of thorns," he says, referring to Gibson's 2004 film, "The Passion of the Christ".
"We are loaded with pictures of this well-defined punishment called crucifixion - and that is the problem," he says.
Samuelsson bases his claim on studying 900 years' worth of ancient texts in the original languages - Hebrew, Latin and Greek, which is the language of the New Testament.
He spent three years reading for 12 hours a day, he says, and he noticed that the critical word normally translated as "crucify" doesn't necessarily mean that.
"He was handed over to be 'stauroun,'" Samuelsson says of Jesus, lapsing into Biblical Greek to make his point.
At the time the apostles Matthew, Mark, Luke and John were writing their Gospels, that word simply meant "suspended," the theologian argues.
"This word is used in a much wider sense than 'crucifixion,'" he says. "It refers to hanging, to suspending vines in a vineyard," or to any type of suspension.
"He was required to carry his 'stauros' to Calvary, and they 'stauroun' him. That is all. He carried some kind of torture or execution device to Calvary and he was suspended and he died," Samuelsson says.
Not everyone is convinced by his research. Garry Wills, the author of "What Jesus Meant," "What Paul Meant," and "What the Gospels Meant," dismisses it as "silliness".
"The verb is stauresthai from stauros, cross," Wills said.
Samuelsson wants to be very clear about what he is saying and what he is not saying.
Most importantly, he says, he is not claiming Jesus was not crucified - only that the Gospels do not say he was.
"I am a pastor, a conservative evangelical pastor, a Christian," he is at pains to point out. "I do believe that Jesus died the way we thought he died. He died on the cross".
But, he insists, it is tradition that tells Christians that, not the first four books of the New Testament.
"I tried to read the text as it is, to read the word of God as it stands in our texts," he says - what he calls "reading on the lines, not reading between the lines".
Samuelsson says he didn't set out to undermine one of the most basic tenets of Christianity.
He was working on a dissertation at the University of Gothenburg in Sweden when he noticed a problem with a major book about the history of crucifixion before Jesus.
What was normally thought to be the first description of a crucifixion - by the ancient Greek historian Herodotus - wasn't a crucifixion at all, but the suspension of a corpse, Samuelsson found by reading the original Greek.
The next example in the book about crucifixion wasn't a crucifixion either, but the impaling of a hand.
Samuelsson's doctoral advisor thought his student might be on to something.
"He recommended I scan all the texts, from Homer up to the first century - 900 years of crucifixion texts," Samuelsson recalled, calling it "a huge amount of work".
But, he says, "I love ancient texts. They just consume me". So he started reading.
He found very little evidence of crucifixion as a method of execution, though he did find corpses being suspended, people being hanged from trees, and more gruesome methods of execution such as impaling people by the belly or rectum.
The same Greek word was used to refer to all the different practices, he found.
That's what led him to doubt that the Gospels specify that Jesus was crucified.
At the time they were written, "there is no word in Greek, Latin, Aramaic or Hebrew that means crucifixion in the sense that we think of it," he says.
It's only after the death of Jesus - and because of the death of Jesus - that the Greek word "stauroun" comes specifically to mean executing a person on the cross, he argues.
He admits, of course, that the most likely reason early Christians though Jesus was crucified is that, in fact, he was.
But he says his research still has significant implications for historians, linguists and the Christian faithful.
For starters, "every book on the history of Jesus will need to be rewritten," as will the standard dictionaries of Biblical Greek, he says.
More profoundly, his research "ought to make Christians a bit more humble," he says.
"We fight against each other," he reflects, but "the theological stances that keep churches apart are founded on things that we find between the lines.
"We have put a lot of things in the Bible that weren't there in the beginning that keep us apart. We need to get down on our knees as Christians together and read the Bible".