Then, it was gone. In 1767, the Burmese invaded the capital city of the kingdom, also known in the West as Siam, and left it in ruins. Its records were obliterated and treasures destroyed, scattered and lost to memory, some buried deep in the sacred chambers.

But a small number of artifacts survived the conquest of the kingdom, located in the central part of present-day Thailand. And centuries after the fall of Ayutthaya (pronounced ah-YOOT-tah-yah), examples of its most important artwork has been gathered in an exhibit that opened over the weekend at the Peabody Essex Museum.

"The Kingdom of Siam: The Art of Central Thailand, 1350-1800," includes 80 items gathered from collections in Europe, the United States and Thailand. Among the pieces: a 6-foot-high bronze Buddha head, manuscripts illustrated with rare art and an inscription on a stone relief that helped scholars discover the lost letters of the kingdom's alphabet.

The show, on display until Oct. 16 in its only East Coast stop, took shape after seven years and extensive diplomatic efforts to bring it all to one place. Dan Monroe, director of the Peabody Essex Museum, said that besides giving a look into a largely forgotten culture, the exhibit reinforces a historical truth.

"It's the art of a nation and culture that outlasts them, that speaks for them over a period of time," he said.

In the 18th-century attack on the capital city, also called Ayutthaya, the invading Burmese burned it down, plundered its valuables and tortured local people for the location of its treasures, said Forrest McGill, the exhibit's curator.

Ayutthaya, located about 30 miles north of present-day Bangkok, was eventually reinhabited, but McGill said it was in such ruins that there was minimal interest in exploring its past. Artifacts are so rare, he said, that a painting on a manuscript that seemed to match a painting on a cloth were major finds merely because they appeared to be done by the same artist.

When putting the exhibit together, scholars discovered new information about Siam.

A stone sculpture of a walking Buddha was pried from the storeroom wall in a Thai museum for the exhibit, and researchers were surprised to find a 20-line inscription on the back. Some of the characters in the inscription, which detailed one family's donation to the temple, were previously unknown letters in the Thai-Ayutthaya alphabet.

The sculpture is displayed next to the massive Buddha head that greets visitors entering the four-room gallery. Behind it is a display of royal treasure discovered in the late 1950s by thieves who broke into a sacred chamber in one of Ayutthaya's temples. The government later recovered much of what was taken from the chamber, which had been sealed since 1424.

More recent artifacts include a wooden cabinet decorated in gold with a figure widely thought to be King Louis XIV of France, who received envoys from Siam in the late 17th century.

Susan Bean, the museum's curator of South Asian and Korean Art and Culture, said the limited artifacts reveal the kingdom as a cosmopolitan place, open to a range of political and cultural influences, including European, Cambodian, Chinese and Sri Lankan.

The more that's known about the art, the more that's revealed about the lost kingdom, Bean said.

"You begin to put the pieces of the jigsaw puzzle together," she said.