In previous articles on the Mongol Empire at war, we discussed some of the things that made this army so spectacularly successful: training, archery, discipline, breakup of tribal groups, Mongol horses and mobility and speed. While all those were necessary to the success, there remains a few equally important strategic elements employed by the Mongol Empire’s armies.

Reconnaissance and Intelligence

Genghis Khan innately understood the need for reconnaissance and intelligence in war. The Great Khan and all his successors sent out scouts and spies in advance of any campaign; they required vital information on roads, trade routes, cities, population, terrain and politics of the land or nation. Before invading Eastern Europe, for example, Subutai, the Mongol’s greatest general, had spies implanted deep into European territories 10 years before the actual invasion of Poland and Hungary.

All militaries have used spies as information is vital for any war effort, but the Mongols were masters of the trade. They patiently invited informants and used spies extensively to understand what they were facing before ever deciding on battle.

Siege Warfare

When the Mongol army first encountered a walled city in northern Chinese territory, they quickly realized that their cavalry was useless. They quickly found experts in siege warfare who could build the machines to batter the walls into rubble. The Mongols recruited engineers from among their captives who built the catapults and siege towers necessary to conquer walled cities. From then on, these specialist engineers traveled with the Mongol armies to rebuild siege engines wherever needed. Before sacking a conquered city, the Mongol army would search out any engineers and separate them from the doomed general population.

The Mongol army became expert in siege warfare to the point that walled cities became obsolete; none could successfully resist the Mongols, who used their expert techniques repeatedly. The Mongols would do anything to conquer a city, including diverting rivers and using captives in the front line of battle.

Psychological Warfare

The Mongols were expert at the tactics of terror. Whenever they routed an enemy, they left a few alive to carry tales of the terrible bloodshed inflicted on the population. When a city resisted the Mongols, all of the inhabitants would be killed except a few, who were allowed run to the next towns. These survivors told of piles of decapitated heads by the gates of destroyed cities and other atrocities. While many thousands died at the hands of the Mongol armies, these terror tactics actually saved lives as the next city encountered submitted immediately to Mongol demands. Conquered cities had to pay tribute and support the Mongol army, but they remained intact and unmolested.

The Mongols were greatly feared for their use of spies and informants, for successful sieges and terror tactics. For over half a century from 1206 to 1260, Mongol armies won battle after battle; they were an unstoppable force that terrified the world.