Jesus
Could Jesus' followers have made up the resurrection?
For a lie like this to work, a group of people would have needed to agree on the story, stick to it under pressure, and gain nothing obvious for their trouble. Most of Jesus' early followers faced ridicule, poverty, or violence for continuing to preach that he had risen—not money, power, or comfort.
The story also includes a detail that would have hurt it if it were invented. In that culture, a woman's testimony wasn't considered reliable enough for court, yet all four Gospels agree that women discovered the empty tomb first. A committee inventing a convincing lie had no obvious reason to include that.
None of this proves the resurrection happened. But a deliberate conspiracy is a much harder theory to defend than it first sounds, and most historians—believing or not—don't treat it as a serious contender anymore.
Bible quotations in these answers are generally taken from the Christian Standard Bible®, Copyright © 2017 by Holman Bible Publishers. Used by permission. Christian Standard Bible® and CSB® are federally registered trademarks of Holman Bible Publishers. Some biblical wording may be paraphrased or follow other translations.