And tomorrow, we will see the legendary shroud of turin for the first time in 30 years, amid reports of new and mysterious evidence about the sacred relic. Here's abc's alex perez. Reporter: For the first time in 40 years, new images of the shroud of turin will be broadcast on television, the event marked by an introduction by pope francis himself. Believers are convinced the shroud covered jesus' crucified body. The fabric is covered in blood stains, dirt and water marks, but its most often-debated attribute, this -- the outline of a face. 1988 research seen here in this documentary, used carbon dating to determine the cloth was from medieval times and the whole thing was a hoax. But a new book by an italian professor argues those tests were performed on fibers used to repair the shroud in the middle ages, that the cloth itself is from jesus' time. When you consider that there are no substances on the cloth that were conceivably used by an artist and the fact that the blood on the cloth is human blood, it would suggest that the cloth is probably authentic. Reporter: But how did that image get there? One theory -- ammonia vapor released by a body mixed with the linen. No confirmed relics exist of jesus' life, but historians agree he lived. In about 93 a.D., The roman historian josephus wrote about a man named jesus, describing "a wise man, if it be lawful to call him a man, for he was a doer of wonderful works." Other roman authors wrote of his baptism by john the baptist, his crucifixion by the roman emperor pontius pilate. The mystery of the shroud of turin has boggled minds here at the vatican and around the world for centuries, but some say whether it's real or not doesn't matter. Does it matter if it is real or not? I think it depends on the person. I think it's really an individual choice and that for some people, what really matters is just the symbolic, what it respects. Reporter: And for many, believing jesus was wrapped in this cloth is more important than knowing. Alex perez, abc news, rome.