The Fifth Gospel

The Fifth Gospel (2015), a historical mystery by Ian Caldwell, centers on a serial murderer targeting Catholic priests, and one priest’s mission to find the killer before it’s too late. The book received high praise upon publication for its unique historical angle and its emotive writing style. In 2016, The Fifth Gospel received the ITW Thriller Award for Best Hardcover. Caldwell is a bestselling American novelist well-known for his historical thrillers and mysteries. His debut novel, The Rule of Four (2004), is semi-autobiographical. Caldwell is often compared to Dan Brown due to the similar subject matter their books cover.

The catalyst for the plot is the mysterious and mystical Shroud of Turin. A researcher, Ugo Nogara, plans to stage an exhibit of the Shroud in the Vatican. He has spent many years researching the Shroud. Although science supposedly proved that the Shroud is fake and never existed, Ugo has reason to believe otherwise. He’s convinced that the carbon testing discrepancies he’s identified prove the Shroud is real.

Days before the exhibit opens, Ugo is found murdered on the outskirts of Rome. Ugo was a popular man, and no one can understand who would want him dead. The Pope’s own office takes a special interest in the case, given the gravity of what’s happened. Many are saddened that the exhibit can’t now go ahead, but others are relieved. It becomes apparent that there’s a secret about the Shroud that the Catholic Church doesn’t want to be revealed.



Father Alex Andreou is a Greek Catholic priest. He teaches the gospels to Vatican students. Having married before taking his vows, he has a son. His brother, Father Simon, is a Roman Catholic priest. Within the one family, then, the two main strands of the Catholic religion are represented—Catholicism and Orthodoxy. At the time, Pope John Paul II’s dying wish was to reunite these conflicting branches. This is important to the general theme of the novel.

The night Ugo is murdered, Father Simon phones Father Alex, asking him for help. Father Simon was found standing over Ugo’s dead body, and the papal police try to blame him for the murder. Ugo is one of Father Simon’s best friends, so Father Alex doesn’t believe this is possible. He’s convinced that someone else is responsible.

On the same evening, someone breaks into Father Alex’s home. It’s not clear if they stole anything, but they were clearly hunting for something. The papal police, however, aren’t very interested in the break-in. Father Alex senses that something isn’t right with how everyone is reacting. Knowing he’s the only one who will try to prove his brother’s innocence, he vows he won’t stop trying until he uncovers the real perpetrator.



Father Alex knows that Ugo cataloged all his research on the Shroud. He kept his information secret, but Father Alex can’t help thinking that the Shroud has something to do with Ugo’s murder and the break-in at his own home. Since the papal police refuse to listen to his theories, he decides to discover the truth behind the Shroud himself. To do so, he must investigate what’s known as the Diatessaron.

The Diatessaron is the fifth gospel, which no one knows much about. All they know is that it is supposed to bring together the four earlier gospels, uniting them to heal divisions between Christian sects. Within the Diatessaron is the truth that exposes discrepancies between historical truth and fiction. Knowing Ugo studied this gospel and its purpose, Father Alex believes Ugo discovered a dangerous secret within its pages.

Father Alex must first return to the four gospels he knows of. He identifies many discrepancies—each apostle who wrote the gospels recounts history in a very different way. Evaluating the gospels, and challenging his understanding of the Shroud, goes against everything he was taught as a young boy; it’s very difficult for him. To make matters worse, someone is following him—and they want him to stop looking for answers about the Shroud.



Father Alex can’t help feeling that there’s a larger meaning to all this, particularly since the Pope wanted Christian sects to heal. Before he died, Father Alex’s own father campaigned, fighting to unite the two sides, but he failed. Father Alex is fighting now both for his brother and his father’s memory.

As Father Alex studies the gospels, he focuses his attention on the Gospel of John. He notices that John is the only gospel in which there’s any mention of a wound in Jesus’s side, which causes a bloodstain on the Shroud. John typically embellished his descriptions and, according to Father Alex, his conclusions are very unreliable. Because of this, Father Alex says the Shroud is a fake. The bloodstain was added on years later to make it look reliable.

At the same time, the papal police uncover evidence that shows that Ugo killed himself. His motives, however, are unclear. Father Simon is freed, reunited with his brother who never lost faith in him. From a thematical point of view, the divisions between family and church are all “healed.” The novel is otherwise left open-ended.