Queen Mary wearing La Peregrina

One painting in the exhibit illustrates a historical mystery that stands a good chance of being true, but has never been conclusively proved. The 1554 oil by Hans Eworth shows Queen Mary dressed in a sumptuous gown and jewels, including an oblong pearl suspended on a necklace.

"The pearl was discovered in 1513 by a Portuguese sailor, one of the most perfect natural pearls ever found, and one of the largest, more than 50 carats. It was acquired by the Spanish royal family, and then given to Mary by Phillip of Spain as a wedding gift," Fairman said. "After she died in 1558, the Spanish crown retrieved it. Centuries later, Napoleon took it."

Bonaparte gave it to a relative, who lost it, she said. "It becomes a bit murky after that, but it is believed that the pearl, which was now called 'La Peregrina,' the pilgrim, because of how far it traveled, was sold in 1969 to Richard Burton, who gave it to Elizabeth Taylor as a Valentine's Day gift."

Taylor's jewel, set in a necklace, was sold last December at auction for $11.8 million. But is Liz's pearl the same pearl as seen in the painting?

"I really want it to be," Fairman said. "I hope it is."

More about Britain histories