When Gregor MacGregor returned to England from the New World in 1820, he brought auspicious news: He had been created prince of Poyais, a Central American nation of 12,500 square miles.

The Scottish soldier became the toast of London and was soon entertaining dignitaries at elaborate banquets. He published a glowing guidebook, raised a loan of £200,000 for his new government, and began selling land rights to excited settlers.

But when two ships arrived at the described location in 1823, they found nothing but jungle. Lacking shelter and beset by disease, the settlers had to be evacuated to British Honduras, and only 70 of the 250 survived. A warning reached London in time to stop five additional ships from making the voyage.

A furor erupted, but by that time MacGregor had left for France, where he attempted the same hoax. Officials there locked him up, but he was acquitted at trial and brazenly returned to England, where he kept up similar schemes through 1837. He died, blithely, in Venezuela in 1845.

Grey Owl (1888-1938), left, a pioneer in Canadian conservation, turned out to be Archibald Belaney, a farmer’s son from Hastings, England.

Two Moon Meridas (1888-1933), right, a promoter of herbal medicines, was really Chico Colon Meridas.

Meridas must have been pretty convincing — when he was indicted in 1932, 26 Sioux spoke in his defense.

In the 1920s, American painter and eccentric Waldo Peirce gave a turtle to the concierge of the building in which he lived. She was delighted with the gift and took great care of her new pet, and she did not notice when Peirce secretly replaced it with a slightly larger turtle. This continued for some time, with Peirce sneaking successively larger turtles into her apartment while she praised her miraculous pet to the neighbors.

Then, after a suitable pause, he began using smaller turtles.

London conjuror Chung Ling Soo was famous for his “bullet catch” illusion: Audience members would mark bullets that were loaded into a gun, which attendants then fired at Soo. He would appear to catch the bullets and drop them on a plate. In fact, Soo palmed the bullets during the marking, and alternate bullets were loaded into the gun, which was rigged to swallow them and fire a harmless gunpowder charge.

That worked fine until March 23, 1918, when the gun didn’t swallow. A live audience in the Wood Green Empire watched the attendant shoot Soo — who staggered and said, “My God, I’ve been shot” in English. Not only had he faked catching bullets, William Robinson had faked being Chinese for 19 years. He died the next day.

Anyone can lead a fascinating life if he’s willing to invent it out of whole cloth. Or at least that’s the lesson of George Psalmanazar, one of the stranger figures in European history.

Born in France in 1679, Psalmanazar traveled to Scandinavia in 1700 and perversely told everyone he was from Formosa. And he didn’t stint on details. In Formosa, he said:

• Horses and camels were used for mass transportation.
• Men walked naked, covering their privates with gold and silver plates.
• The chief food was a serpent, hunted with branches.
• A man could have many wives; if any was unfaithful he could eat her.
• Murderers were hung upside down and shot full of arrows.
• Formosans sacrificed 18,000 young boys to gods each year, and priests ate the bodies.

Psalmanazar eventually found he could make a career of this; he gave lectures and wrote a book that went through two English editions and was translated into French and German. To keep up “Formosan” appearances, he ate raw meat, slept upright in a chair, and claimed to worship the sun and moon. Eventually, though, he gave up the charade, confessing in 1706.

To this day, no one knows who he really was — he never gave his real name.

On June 25, 1899, all four major Denver newspapers, the Times, the Post, the Republican, and the Rocky Mountain News, ran front-page stories saying that the Chinese were planning to demolish the Great Wall of China and build a road in its place.

They weren’t, obviously — the hoax was dreamed up by a cabal of bored reporters — but the story survived and even spread. Two weeks after the Denver publication, a large Eastern newspaper picked it up, adding confirming “quotes” by earnest Chinese and including its own illustrations and comments. Soon the story had spread throughout the United States and even entered Europe.

The full truth didn’t emerge until the last surviving reporter revealed the hoax.