In the early 13th century a band of fierce nomads swept down from the chilly steppes of Mongolia and began one of the bloodiest invasions in history. Eventually the Mongol Empire (1206-1368) would stretch from the Sea of Japan to Hungary.

The Mongols' influence was only regional until a young military genius named Temujin came on the scene. Avenging his father's death, Temujin defeated the enemy Tatars and gradually brought the nomadic tribes of Mongolia under his control. In 1206 the Mongols named him Genghis Khan, or Universal Ruler.

Genghis Khan and his warriors overwhelmed their opponents with superior skill and ruthless tactics. Superb horsemen, the Mongols were fierce fighters armed with lances, sabers, daggers, and bows and arrows.

To terrify the enemy, the men designed some arrowheads to whistle as they flew. And when using a catapult during sieges, the Mongols would often lob diseased human carcasses into their enemies' midst.

Genghis Khan first captured northern China and then turned west, taking Afghanistan, Persia, and parts of Russia. The vanquished were slaughtered by the thousands, while some unlucky survivors were used as human shields in the next fight.

After Genghis Khan's death in 1227, his descendants carried on the fight to expand the Mongol Empire. By the late 13th century, it reached from Hungary to the Sea of Japan. The empire was divided into four nearly autonomous areas called khanates: China, central Asia, Persia, and Russia.

After the death in 1294 of the Great Khan of China, Kublai Khan, the empire broke apart. Mongol conquest resurged in the late 14th century when Timur (the Lame), who claimed to be descended from Genghis Khan, conquered Persia, Iraq, Syria, Afghanistan, and parts of Russia. On the way to attack China, however, Timur died, and the Mongol era was finished.