For me, it has to be the Mongols and here's why:
Genghis Khan and the Mongols: The knights at their tournaments, in their finery, armor and emblems of ancestry, believed they were the foremost
warriors in the world, while Mongol warriors thought otherwise. Mongol horses were small, but their riders were lightly clad and they moved with
greater speed. These were hardy men who grew up on horses and hunting, making them better warriors than those who grew up in agricultural societies
and cities. Their main weapon was the bow and arrow. And the Mongols of the early 1200s were highly disciplined, superbly coordinated and brilliant in
The Mongols were illiterate, religiously shamanistic and sparsely populated, perhaps no more than around 700,000 in number. Their language today is
described as Altaic -- derived from the Altay mountain range in western Mongolia -- a language unrelated to Chinese. They were herdsmen on the grassy
plains north of the Gobi Desert and south of Siberian forests. Before the year 1200, the Mongols were fragmented, moving about in small bands headed
by a chief, or khan, and living in portable felt dwellings -- gers.
The Mongols endured frequent deprivations and sparse grazing. They frequently fought over turf, and during hard times they occasionally raided,
interested in goods rather than bloodshed. They did not collect heads or scalps as trophies and did not notch wood to record their kills.
From his late teens to age thirty-eight in 1200, a Mongol named Temujin (Temüjin) rose as khan over various families. He was a good manager,
collecting people of talent. He was vassal to Ong Khan, titular head of a confederacy better organized than other Mongol clans. Temujin joined Ong
Khan in a military campaign against Tatars to their east, and following the success of this campaign Ong Khan declared Temujin his adoptive son and
heir. Ong Khan's natural son, Senggum (Senggüm), had been expecting to succeed his father and plotted to assassinate Temujin. Temujin learned of
this, and those loyal to Temujin defeated those loyal to Senggum. Temujin was now established as the head of what had been Ong Khan's coalition. And
in 1206, at the age of 42, Temujin took the title Universal Ruler, which translates to Genghis Khan, and he addressed his joyous supporters thanking
them for their help and their loyalty.
Like others, Genghis Khan's subjects saw themselves at the center of the universe, the greatest of people and favored by the gods. They justified
Genghis Khan's success in warfare by claiming that he was the rightful master not only over the "peoples of the felt tent" but the entire world.
Genghis Khan continued organizing. He improved his military organization, which was also to serve as a mobile political bureaucracy, and he broke up
what was left of old enemy tribes, leaving as ethnically homogeneous only those tribes that had demonstrated loyalty to him. He created a body of
law that he was to work on throughout his life. The kidnapping of women had caused feuding among the Mongols, and, as a teenager, Temujin had suffered
from the kidnapping of his young wife, Borte, whom he had devoted himself to rescuing, and he made it law that there was to be no kidnapping of women.
He declared all children legitimate, whomever the mother. He made it law that no woman would be sold into marriage. The stealing of animals had caused
dissention among the Mongols, and Genghis made it a capital offense. A lost animal was to be returned to its owner, and taking lost property as one's
own was to be considered thievery and a capital offense. Genghis regulated hunting -- a winter activity -- improving the availability of meat for
everyone. He introduced record keeping, taking advantage of his move years before to have his native language put into writing. He created official
seals. He created a supreme officer of the law, who was to collect and preserve all judicial decisions, to oversee the trials of all those charged
with wrongdoing and to have the power to issue death sentences. He created order in his realm that strengthened it and his ability to expand.
Conquests in Northern China
Genghis Khan moved to secure his borders. To his south he made an alliance with the Uighurs, who were closer than the Mongols were to the Silk Road
and to wealth. Genghis married his daughter to the Uighur Khan, and the Uighur Khan brought to the wedding party a caravan laden with gold, silver,
pearls, brocaded fabrics, silks and satins. The Mongols had only leather, fur and felt -- a humiliation for a master of the entire world. Genghis
needed booty to pay troops securing his northern border and subduing an old enemy there, the Merkits. Genghis acted on his mandate as the rightful
ruler of the entire world and attacked the rulers of farmers and herders in northwestern China, the Tangut, who had much in goods like the Uighur
Khan. In warriors the Mongols were outnumbered two to one, and they had to learn a new kind of warfare, against fortified cities, including cutting
supply lines and diverting rivers. Genghis Khan and his army were victorious, and in 1210 Genghis won from the Tangut recognition as overlord.
Also in 1210, the Ruzhen, who ruled that part of northern China that included Beijing, sent a delegation to Genghis Khan demanding Mongol submission
as vassals. The Ruzhen (Jin) controlled the flow of goods along the Silk Road, and defying them meant a lack of access to those goods. Genghis Khan
and the Mongols discussed the matter and chose war. Genghis, according to the scholar Jack Weatherford, prayed alone on a mountain, bowing down and
stating his case to "his supernatural guardians," describing the grievances, the tortures and killings that generations of his people had suffered
at the hands of the Ruzhen. And he pleaded that he had not sought war against the Ruzhen and had not initiated the quarrel. NOTE
In 1211, Genghis Khan and his army attacked. The Ruzhen had a large and effective army but they were hard pressed by both the Mongols and by a border
war with the Tangut. They were also under attacked by Chinese from south of the Yangzi River, the Southern Song emperor wishing to take advantage of
the Ruzhen-Mongol conflict to liberate northern China. But the Ruzhen drove the Chinese armies into retreat.
The Mongols were benefiting from China having failed during the previous century to make itself a strong military power. They benefited too from the
Ruzhen ruling conquered people. The Mongols used divide and conquer tactics, using benevolence toward those who sided with them and terror and
bloodshed against those who did not. They ravaged the countryside, gathering information and booty and driving populations in front of them, clogging
the roads and trapping the Ruzhen within their cities, where the Ruzhen were subject to revolts. They used conscripted labor in attacking cities and
in operating their newly acquired Chinese siege engines. The Mongols had an advantage in diet, which included a lot of meat, milk and yogurt, and they
could miss a day or two of eating better than Ruzhen soldiers, who ate grains. Genghis Khan and his army overran Beijing and pushed into the heartland
of northern China. Military success helped as people acquired the impression that Genghis Khan had the Mandate of Heaven and that fighting against him
was fighting heaven itself.
The Ruzhen emperor recognized Mongol authority and agreed to pay tribute, and, after six years of fighting, Genghis Khan returned to Mongolia, leaving
one of his best generals in charge of Mongol positions opposite the Ruzhen. Returning with Genghis Khan and his Mongols were engineers who had become
a permanent part of their army, and there were captive musicians, translators, doctors and scribes, camels and wagonloads of goods. Among the goods
were silk, including silken rope, cushions, blankets, robes, rugs, wall hangings, porcelain, iron kettles, armor, perfumes, jewelry, wine, honey,
medicines, bronze, silver and gold, and much else. And goods from China would now come in a steady flow.
The Mongols were happy to be back from China, their homeland higher in elevation, less humid and cooler. They had looked down on the peoples of
northern China, seeing them as eating grain like cattle and closely packed together as were herds. But they liked what China had to offer, and at home
there was change. The continuing flow of goods from China had to be administered and properly distributed, and buildings had to be built to store the
goods. Success in war was changing the Mongols -- as it had the Romans and the Arabs.
Into Afghanistan and Persia
Genghis Khan wanted trade and goods, including new weapons, for his nation. A Mongol caravan of several hundred merchants approached a recently formed
empire between Persia to Central Asia. The sultan of this kingdom claimed that spies were in the caravan. Genghis Khan sent envoys, and the sultan had
the chief of the envoys killed and the beards of the others burned, and these others he sent back to Genghis Khan. And Genghis retaliated, sending his
In the coldest of months the Mongols rode across the desert to Transoxiana with no baggage, slowing to the pace of merchants before appearing as
warriors before the smaller towns of the sultan's empire. Their strategy was to frighten their opponents into surrendering without battle, benefiting
his own troops, whose lives he valued. Those frightened into surrender were spared violence, those who resisted were slaughtered as an example for
others, which sent many fleeing and spreading panic from the first towns to the city of Bukhara. People in Bukhara opened the city's gates to the
Mongols and surrendered. Genghis Khan told them that they, the common people, were not at fault, that high-ranking people among them had committed
great sins that inspired God to send him and his army as punishment. The sultan's capital city, Samarkand, surrendered. His army surrendered, and he
Genghis Khan and his army pushed more deeply into the sultan's empire -- into Afghanistan and then Persia. It is said that the caliph in Baghdad was
hostile toward the sultan and supported Genghis Khan, sending him a regiment of European crusaders who had been his prisoners. Genghis, having no need
for infantry, freed them, with those making it to Europe spreading the first news of the Mongol conquests.
Genghis Khan had 100,000 to 125,000 horsemen, with Uighur and Turkic allies, engineers and Chinese doctors -- a total of from 150,000 to 200,000 men.
To show their submission, some offered food to the Mongols, and Genghis Khan's force guaranteed them protection. Some cities surrendered without
fighting. In cities the Mongols were forced to conquer, after killing its fighting men, Genghis divided the survivors by profession. He drafted the
few who were literate and anyone who could speak various languages. Those who had been the city's most rich and powerful he wasted no time in
killing, remembering that the rulers he had left behind after conquering the Tangut and Ruzhen had betrayed him soon after his army had withdrawn.
The Mongols did not torture, mutilate or maim, but their enemies did. Captured Mongols were dragged through streets and killed for sport and to
entertain city residents. The Mongols did not partake in the gruesome displays that European rulers often resorted to elicit fear and discourage
potential enemies -- none of the stretching, emasculating, belly cutting and hacking to pieces that, for example, was soon to happen to William
Wallace at the hands of the English. The Mongols merely slaughtered, preferring to do so at a distance.
The city of Nishapur revolted against Mongol rule. The husband of Genghis Khan's daughter was killed, and, it is said, she asked that everyone in the
city be put to death, and, according to the story, they were.
Into Azerbaijan, Armenia and Eastern Europe
While Genghis Khan was consolidating his conquests in Persia and Afghanistan, a force of 40,000 Mongol horsemen pushed through Azerbaijan and Armenia.
They defeated Georgian crusaders, captured a Genoese trade-fortress in the Crimea and spent the winter along the coast of the Black Sea. As they were
headed back home they met 80,000 warriors led by Prince Mstitslav of Kiev. The battle of Kalka River (1223) commenced. Staying out of range of the
crude weapons of peasant infantry, and with better bows than opposing archers, they devastated the prince's standing army. Facing the prince's
cavalry, they faked a retreat, drawing the armored cavalry forward, taking advantage of the vanity and over-confidence of the mounted aristocrats.
Lighter and more mobile, they strung out and tired the pursuers and then attacked, killed and routed them.
In 1225, Genghis Khan returned to Mongolia. He now ruled everything between the Caspian Sea and Beijing. He looked forward to the Mongols benefits of
caravan trade and drawing tribute from agricultural peoples in the west and east. He created an efficient pony express system. Wanting no divisions
rising from religion, he declared freedom of religion throughout his empire. Favoring order and tax producing prosperity, he forbade troops and local
officials to abuse people.
Soon again, Genghis Khan was at war. He believed that the Tangut were not living up to their obligations to his empire. In 1227, around the age of
sixty-five, while leading the fighting against the Tangut, Genghis Khan, it is said, fell off his horse and died.
In terms of square miles conquered, Genghis Khan had been the greatest conqueror of all time -- his empire four times larger than the empire of
Alexander the Great. The Mongol nation believed that he had been the greatest man of all time and a man sent from heaven. Among the Mongols he was
known as the Holy Warrior, and not unlike the Jews, who continued to see hope in a conquering king (messiah) like David, Mongols were to continue to
believe that one day Genghis Khan would rise again and lead his people to new victories.
I suppose after the Mongols, it would have to be the Gauls & Huns, then perhaps the Romans.
Having said that, the Ancient Greeks, Egyptians and Ottoman Empires have all, in their own way, contributed to the world as we know it today.