Polo, the favorite sport of Britain's Prince Charles and the international jet set, was also a popular recreation and diplomatic activity during the ancient Chinese Tang Dynasty (618-907 AD), according to historians.

Duan Xiaoqiang, a lecturer of the history department of the China Northwest Institute for Nationalities, has found two detailed descriptions of a very similar game in an historical document excavated from the Dunhuang Grottoes in northwest China's Gansu Province.

He said the document provides convincing references to the game.

Duan said the then polo balls were made of wool and covered in leather, and the sticks looked more like modern hockey sticks. With long handles, the painted and carved wooden sticks had crescent-shaped heads and usually measured several feet long.

Like modern polo, the ancient game was also played by two teams of three or four players on horseback.

Before each game, horses' tails would be coiled and decorated with ornaments, he said.

There was no hard and fast rules on the size of the playing fields so long the land was smooth and firm. Winner was claimed by the side with the higher score which was recorded with 12 colored flags erected on both sides of the two goals.

According to the documents, two referees gave orders and decisions by waving red flags.

Each team would have their own supporters who spurred the players on with music and drumbeats.

"As the games were held mainly for entertainment rather than competition, there were no rigid stipulations on the equipment, courts and rules," Duan said.

Some players even competed on donkey-back and the rival teams might have different numbers.

Records show that sometimes there was only one goal erected in the middle of the field so as to see which player could achieve the highest score.

Duan said many emperors of the Tang Dynasty were fans of the game, not only playing themselves, but encouraging officials, soldiers, civilians even maids-in-waiting to join in.

According to Duan, emperors of the Tang Dynasty also viewed the game as an important diplomatic activity through which ties with neighboring ethnic regimes, including the Tibetan Regime, became increasingly close and safe.

Although no available references can prove a direct link between the ancient game and modern polo, Duan said the documents were valuable for research into the development of the ancient game.

Duan said the historical documents detailed the history of the game and recorded the past prosperity of the Tang Dynasty.