SAN FRANCISCO - A 200-year-long drought 4,200 years ago may have killed off the ancient Sumerian language, one geologist says.

Because no written accounts explicitly mention drought as the reason for the Sumerian demise, the conclusions rely on indirect clues. But several pieces of archaeological and geological evidence tie the gradual decline of the Sumerian civilization to a drought.

The findings, which were presented Monday (Dec. 3) here at the annual meeting of the American Geophysical Union, show how vulnerable human society may be to climate change, including human-caused change.

Archaeologists have found the remains of an ancient imperial palace near the tomb of emperor Qin Shi Huang, home of the famous terracotta army, China's state media reported on Sunday. The palace is the largest complex discovered so far in the emperor's sprawling 22 square-mile (56 square-km) second-century BC mausoleum, which lies on the outskirts of Xi'an, an ancient capital city in central China, an associate researcher at the Shaanxi provincial institute of archaeology told China's official news wire Xinhua.

It is an estimated 690 metres long and 250 metres wide - about a quarter of the size of the Forbidden City in Beijing - and includes 18 courtyard-style houses with one main building at the centre, according to the researcher, Sun Weigang. Sun called the palace a clear predecessor to the Forbidden City, which was occupied by emperors during the later Ming and Qing dynasties. Both were built on north-south axes in keeping with traditional Chinese cosmology.

The obscure book's margins are virtually filled with clusters of curious foreign characters - a mysterious shorthand used by 17th century religious dissident Roger Williams.

For centuries the scribbles went undeciphered. But a team of Brown University students has finally cracked the code.

Historians call the now-readable writings the most significant addition to Williams scholarship in a generation or more. Williams is Rhode Island's founder and best known as the first figure to argue for the principle of the separation of church and state that would later be enshrined in the Bill of Rights.

His coded writings are in the form of notes in the margins of a book at the university's John Carter Brown Library. The nearly 250-page volume, "An Essay Towards the Reconciling of Differences Among Christians," was donated in the 1800s and included a handwritten note identifying Williams as the notes' author - though even that was uncertain at first.

A group including former library director Edward Widmer, Williams scholar and Rhode Island College history professor emeritus J. Stanley Lemons and others at Brown started trying to unravel the so-called "Mystery Book" a few years ago. But the most intense work began this year after the university opened up the challenge to undergraduates, several of whom launched an independent project.

Ancient people probably assembled the massive sandstone horseshoe at Stonehenge more than 4,600 years ago, while the smaller bluestones were imported from Wales later, a new study suggests.

The conclusion, detailed in the December issue of the journal Antiquity, challenges earlier timelines that proposed the smaller stones were raised first.

"The sequence proposed for the site is really the wrong way around," said study co-author Timothy Darvill, an archaeologist at Bournemouth University in England. "The original idea that it starts small and gets bigger is wrong. It starts big and stays big. The new scheme puts the big stones at the center at the site as the first stage."

The new timeline, which relies on statistical methods to tighten the dates when the stones were put into place, overturns the notion that ancient societies spent hundreds of years building each area of Stonehenge. Instead, a few generations likely built each of the major elements of the site, said Robert Ixer, a researcher who discovered the origin of the bluestones, but who was not involved in the study.

"It's a very timely paper and a very important paper," Ixer said. "A lot of us have got to go back and rethink when the stones arrived."

Pieces of a medieval board game and 1,000-year-old combs are among rare artefacts uncovered during an archaeological dig that is set to rewrite the history books. Experts have hailed the finds in Co Fermanagh as internationally significant, claiming they shed new light on life in medieval Ireland and its connection with the wider world.

Iron, bronze and bone ornaments have been discovered at the crannog just outside Enniskillen, along with the chess-like pieces believed to have been part of the game. Parts of log boats, leather shoes, knives, decorated dress pins, wooden vessels and a bowl with a cross carved on its base have also been unearthed during the six-month dig.

Call it a card player's dream. A complete set of 52 silver playing cards gilded in gold and dating back 400 years has been discovered.

Created in Germany around 1616, the cards were engraved by a man named Michael Frömmer, who created at least one other set of silver cards.

According to a story, backed up by a 19th-century brass plate, the cards were at one point owned by a Portuguese princess who fled the country, cards in hand, after Napoleon's armies invaded in 1807.

At the time they were created in 1616 no standardized cards existed; different parts of Europe had their own card styles. This particular set uses a suit seen in Italy, with swords, coins, batons and cups in values from ace to 10. Each of these suits has three face cards - king, knight (also known as cavalier) and knave. There are no jokers. [See Photos of the Silver Playing Cards]

In 2010, the playing cards were first put on auction by an anonymous family at Christie's auction house in New York. Purchased by entrepreneur Selim Zilkha, the cards were recently described by Timothy Schroder, a historian with expertise in gold and silver decorative arts, in his book Renaissance and Baroque Silver, Mounted Porcelain and Ruby Glass from the Zilkha Collection (Paul Holberton Publishing, 2012).

"Silver cards were exceptional," Schroder writes. "They were not made for playing with but as works of art for the collector's cabinet, or Kunstkammer." Today, few survive. "[O]nly five sets of silver cards are known today and of these only one - the Zilkha set - is complete."

On the cards, two of the kings are depicted wearing ancient Roman clothing while one is depicted as a Holy Roman Emperor and another is dressed up as a Sultan, with clothing seen in the Middle East. . The knights and knaves are depicted in different poses wearing (then-contemporary) Renaissance military or courtly costumes. Each card is about 3.4 inches by 2 inches (8.6 centimeters by 5 centimeters) in size and blank on the back.

Archaeologists working in western Cyprus are raising a glass to the discovery of a Bronze Age "microbrewery".

The team excavated a 2 metres x 2 metres mud-plaster domed structure which it says was used as a kiln to dry malt and make beer 3,500 years ago.

Beers of different flavours would have been brewed from malted barley and fermented with yeasts with an alcoholic content of around 5%. The yeast would have either been wild or produced from fruit such as grape or fig, according to the researchers.

Dr Lindy Crewe, from the University of Manchester, has led the excavation at the Early-Middle Bronze Age settlement of Kissonerga-Skalia, near Paphos, since 2007. She said: "Archaeologists believe beer drinking was an important part of society from the Neolithic onwards and may have even been the main reason that people began to cultivate grain in the first place.

"But it's extremely rare to find the remains of production preserved from thousands of years ago so we're very excited. The excavation of the malting kiln with associated sets of pottery types and tools left in place gives us a fantastic opportunity to look at Bronze Age toolkits and figure out techniques and recipes."

Despite a seaside home overlooking the Mediterranean, the very first human settlers of Sicily weren't seafood lovers, new research finds.

In an analysis published today (Nov. 28) in the journal PLOS ONE, skeletal remains of the people who occupied the site around 10,000 years ago show no telltale signs of seafood eating. Instead, researchers say, these hunter-gatherers chowed down on game such as deer and boar.

These first settlers, found on the modern-day island of Favignana, which was once connected to Sicily by a land bridge, probably ate little seafood for two reasons, said study researcher Marcello Mannino, a scientist at the Max Planck Institute for Evolutionary Anthropology in Germany.

First of all, the Mediterranean is relatively nutrient-poor - there just aren't that many fish in the sea. Second, these Mesolithic people likely didn't have the technology to do much fishing.

"The fact that these hunter-gatherers did not develop sophisticated fishing technologies in response to sea-level rise suggests that the potential returns of doing so were insufficient and that their population numbers were probably low," Mannino told LiveScience.

A giant cave that might have helped serve as the inspiration for the mythic ancient Greek underworld Hades once housed hundreds of people, potentially making it one of the oldest and most important prehistoric villages in Europe before it collapsed and killed everyone inside, researchers say.

The complex settlement seen in this cave suggests, along with other sites from about the same time, that early prehistoric Europe may have been more complex than previously thought.

The cave, located in southern Greece and discovered in 1958, is called Alepotrypa, which means "foxhole."

"The legend is that in a village nearby, a guy was hunting for foxes with his dog, and the dog went into the hole and the man went after the dog and discovered the cave," said researcher Michael Galaty, an archaeologist at Millsaps College in Jackson, Miss. "The story's probably apocryphal - depending on who you ask in the village, they all claim it was their grandfather who found the cave."

A necropolis with over 100 burials has been unearthed during archaeological excavations near the village of Marten in northern Bulgaria. The discovery was made by the archaeologist from the Archaeology Museum in the Danube city of Ruse, Deyan Dragoev. The necropolis is on the path of the future gas connection between Bulgaria and Romania.

The site includes tombs from the Thracian times to the times of the First Bulgarian Kingdom. The oldest ones date from the 5th - 4th centuries B.C. Some reveal very interesting rites such as the tomb of a decapitated soldier, whose head was laid on his lap, while others have been buried with gold and silver jewelry or with their dogs.

Some skeletons have deformed skulls, which have been typical for the First Bulgarian Kingdom as a sign of high position in society and of nobility. Noble children then had their heads tightened with headbands in order to change the form of the skull, experts say.