George W. Bush called it Sam Houston's bible. Rick Perry swore on its centuries-old sheepskin four times. And on Tuesday, Texas Gov.-elect Greg Abbott is set to preserve one of the oldest inaugural traditions in the U.S. when he lays his hand on the historic tome to take the oath of office.

But archivists now say it's possible that Texas governors have been duped for centuries.

Caretakers of the brittle, brown 199-year-old holy book long known as the Sam Houston Bible -- a would-be link to the former president of an independent Texas cherished by both Republicans and Democrats -- have evidence that suggests the book may have never belonged to the state's equivalent of George Washington.

More than 30 governors are taking oaths of office this month, with the vast majority placing their palms on bibles pulled from family bookshelves. Most presidents do the same, though President Barack Obama requested Abraham Lincoln's for his first oath.

In Texas, the oath almost exclusively involves Sam Houston, the titan of Texas history who led the fight for independence from Mexico at the Battle of San Jacinto. He was twice president of the Republic of Texas in the 1840s and the state's seventh governor. He is so idolized by Perry that last year the governor was baptized in the small creek where Houston, who struggled with alcohol, once went to be born again.

But quietly over the last five years, archivists at the Texas Supreme Court have questioned the bible's lore. They have filled a thin manila folder with old newspaper clippings that dispute decades of Texas tales about a thieving janitor who tore Houston's signature from the bible during a game of dominoes in the court basement.

"You would think that if he (Houston) had given the bible to the court, and journalists are writing stories about it in the late 1800s, they would have mentioned that," said Texas Supreme Court Clerk Blake Hawthorne, the bible's custodian.

Here are the undisputed facts: The publishing date inside is 1816. The binding is original, but the book was re-cased and is now more flexible. Souvenir-seekers would tear out pages and pocket them, then sheepishly hand them back after being chased down.

Houston's connection to the book is fuzzier, and big clue is long gone: The bible's flyleaf reads "Supreme Court of the Republic of Texas," but the bottom half is torn away. A Texas Supreme Court justice told colleagues in the 1940s that he saw Houston's signature on the now-missing half of the page.

That recollection satisfied amateur historians for a long time. When Bush was inaugurated in 1995, he called it "Sam Houston's own bible, simple and worn."

But the story doesn't quite add up, according to court archivist Tiffany Shropshire.

The torn flyleaf was long blamed on a janitor, who in the 1970s stole thousands of pages of old Supreme Court archives. But the janitor is off the hook -- Shropshire found a 1941 newspaper article that described the torn flyleaf.

She also questions whether Houston ever signed the bible. In 2012, she asked three Houston historians to inspect the handwriting on the remaining portion of the flyleaf. Each said it looked like Houston's. Her skepticism deepened, though. None was a handwriting expert. And letters found in state archives show the penmanship closely resembles that of John Hemphill, the court's first chief justice, she said.

Asked why the court simply didn't hire handwriting experts, Shropshire said, "Those aren't free."

The court would like to put the mystery to rest, and in the meantime have everyone who touches the book wear white gloves. "But I'm not going to ask the governor to put on gloves," Shropshire said.

Proponents of the Sam Houston bible legend are undeterred.

"It still has significant value," said Mac Woodward, who runs the Sam Houston Memorial Museum in Huntsville and believes the handwriting belongs to Houston. "What's most important and what we need to remember is what Sam Houston represented in character."