"All these men with different neighborhoods, different professions meeting in the cafe, breaking bread together, doing rituals -- what could this be?" said UCLA professor Jacob. "So the response on the part of the authorities was, Oh my God, this is a conspiracy!"
And so in 1738 Pope Clement XII issued the Catholic Church's first decree against Freemasonry -- and it still applies today.
In the U.S., Freemasonry flourished until its secrecy made it the object of suspicion here, spawning America's first third party, the Anti-Masonic Party.
It elected eight Congressmen, but lost the 1828 presidential election to Andrew Jackson -- a proud Mason.
Today, Freemasonry has about 1.3 million members in the U.S., down from 4 million in 1959.
Among the members today: African-Americans, formerly relegated to a separate, black-only branch of Freemasonry.
And then there are members like those in Colonial Lodge No. 1821 of Washington, D.C. Most of them are in their twenties, and some were attracted to Freemasonry by Dan Brown novels and movies like "National Treasure."
"Who here was sort of drawn by the mystery?" Rocca asked a group of young Masons.
"I think all of us," they replied.
"I think it's a combination of history [and] tradition," said one.
Another said it was the allure of ritual: "I mean, that's the reason people join Freemasonry and not the Rotarians."
So what about those secrets?
"What would happen if I found out the secret handshake and I weren't a Mason?" Rocca asked. "You wouldn't have to kill me?"
"We might take you out and buy you a beer," said Morris. "The secrets of a Mason represent my integrity as a man. I took a promise that I would not tell you what the secrets of the Mason are. I didn't take a promise that I would care if you know what they are."
Also a big secret : the meetings. No non-Masons, or cameras, are allowed. But St. John's Lodge No. 1 of New York agreed to give us a glimpse of one.
For meetings Masons dress up in their Sunday bests and -- just like the original stonecutters -- wear aprons.