Brad Meltzer’s new book, History Decoded: The 10 Greatest Conspiracies of All Time, provides fascinating insight into 10 of the greatest conspiracies of all time. From D.B. Cooper to the fate of John Wilkes Booth to Area 51, Brad investigates the claims behind some of the most notorious conspiracies in American history.

After talking about D.B. Cooper, the assassination of Abraham Lincoln, and the conspiracy behind the Confederate gold over the last couple of weeks, Brad joined the radio program this morning to talk about the conspiracy of the White House Cornerstone and the Spear of Destiny.

Brad started with a quick recap of the cornerstone controversy.

“So in 1792, the Freemasons put down the very first piece of the White House in a very elaborate ceremony… What’s amazing is 24 hours after they put down this first piece of the White House, it goes missing. No one knows where it is,” Brad said. “For 200 years now, everyone from Harry Truman to Barbara Bush has looked for it. No one found it. No one knows where it is… Everyone says that the free masons took it.”

A self-professed lover of the Freemasons, Brad explained that the conspiracy centers around President Harry Truman, who had pieces of the White House excavated during a renovation and sent to Freemason headquarters around the country.

“They say none of them were the cornerstone. But there’s a conspiracy. He sends 50 pieces across the United States to different lodges, and you are telling me he didn’t take the cornerstone too,” Brad asked. “No one knows. Did he take that piece out? Did he leave it in there? And the only person who knows is Harry Truman. That’s it.”

Brad then moved on to the conspiracy behind the Spear of Destiny.

“The spear of destiny is the spear that pierced Christ’s side while he was on the cross,” Brad explained. “Constantine is the great processes the spear. He supposedly becomes Roman emperor, running the empire because of the spear. And Charlemagne had the spear supposedly… All these world leaders have the spear and the power that comes with it. You know who wanted it in World War II? Hitler. If

Adolph Hitler wants it – I want to know what it is.”

The Vatican says it has the original spear. Another museum in Vienna also claims to have the spear. Meanwhile, Brad met a man during his research named Chris Blake, a professional chauffeur and bodyguard, who claims it was his boss who actually had the original.

“We found a guy who years ago approached me and told me that the real Spear of Destiny that pierced Christ’s side, it was actually taken years ago. They took it from Hitler and gave him a fake one. [Blake] worked for a powerful man, who had the ear of a U.S. president.  We checked out where he worked. He worked for this man, and he said years ago he was told his boss had the real spear. His boss belonged to a group called the Sons of the Fallen…  If you looked at the history, wow, this guy is really involved in a lot of stuff.”

Check out the full interview with Brad below: