How did a first-century Jew called Jesus manage to spark a new religion? Christianity was born nearly two thousand years ago and has won untold millions of followers. Yet, historians still cannot say how it really began. The Signfinally provides the answer. Traditionally, the birth of Christianity has been explained via the miracle of the Resurrection, but historians have been unable to account for Christianity's remarkable success without the Resurrection to spark it. If no one really saw the Risen Jesus, how were people convinced that he was their immortal Messiah? Art historian Thomas de Wesselow has spent the last seven years deducing the answer to this puzzle. Reassessing a much-misunderstood historical source and reinterpreting critical biblical passages, de Wesselow shows that the solution has been staring us in the face for more than a century. The Shroud of Turin, widely thought to be a fake, is, in fact, authentic. And it holds the key to the greatest mystery in human history.