Military of the Mongol Empire

During the Mongol invasions and conquests, which began under Genghis Khan in 1206–1207, the Mongol army conquered most of continental Asia, including parts of West Asia, and parts of Eastern Europe, with further (albeit eventually unsuccessful) military expeditions to various other regions including Japan, Indonesia and India. The efforts of Mongol troops and their allies enabled the Mongol Empire to become the contemporarily largest polity in human history. Today, the former Mongol Empire remains the world's largest polity to have ever existed in terms of contiguous land area and the second-largest polity overall, behind only the British Empire.

Each Mongol soldier typically maintained three or four horses. Changing horses often allowed them to travel at high speed for days without stopping or wearing out the animals. When one horse became tired, the rider would dismount and rotate to another. By letting a tired horse keep up with the rest of the herd without a load, the strategy preserved mobility without overburdening the animal. The Mongols protected their horses in the same way as they did themselves, covering them with lamellar armor. Horse armor was divided into five parts and designed to protect every part of the horse, including the forehead, which had a specially crafted plate that was tied on each side of the neck.

Lamellar armor was worn over thick coats. The armor was composed of small scales of iron, chain mail, or hard leather sewn together with leather tongs and could weigh 10 kilograms (22 lb) if made of leather alone and more if the cuirass was made of metal scales. The leather was first softened by boiling and then coated in a crude lacquer made from pitch, which rendered it waterproof. Sometimes the soldier's heavy coat was simply reinforced with metal plates.

Helmets were cone shaped and composed of iron or steel plates of different sizes and included iron-plated neck guards. The Mongol cap was conical in shape and made of quilted material with a large turned-up brim, reversible in winter, and earmuffs. Whether a soldier's helmet was leather or metal depended on his rank and wealth.

Mounted archers were a major part of the armies of the Mongol Empire, for instance at the 13th-century Battle of Liegnitz, where an army including 20,000 horse archers defeated a force of 30,000 troops led by Henry II, Duke of Silesia, via demoralization and continued harassment.

The primary weapon of the Mongol forces was their composite bows made from laminated horn, wood, and sinew. The layer of horn is on the inner face as it resists compression, while the layer of sinew is on the outer face as it resists tension. Such bows, with minor variations, had been the main weapon of steppe herdsmen and steppe warriors for over two millennia; Mongols (and many of their subject peoples) were skillful archers. Composite construction allows a powerful and relatively efficient bow to be made small enough that it can be used easily from horseback.

Quivers containing 60 arrows were strapped to the backs of their cavalrymen and to their horses. Mongol archers typically carried 2 to 3 bows (one heavier and intended for dismounted use, the other lighter and used from horseback) that were accompanied by multiple quivers and files for sharpening their arrowheads. These arrowheads were hardened by plunging them in brine after first heating them red hot.

The Mongols could shoot an arrow over 200 metres (660 ft). Targeted shots were possible at a range of 150 or 175 metres (492 or 574 ft), which determined the tactical approach distance for light cavalry units. Ballistic shots could hit enemy units (without targeting individual soldiers) at distances of up to 400 metres (1,300 ft), useful for surprising and scaring troops and horses before beginning the actual attack. Shooting from the back of a moving horse may be more accurate if the arrow is loosed in the phase of the gallop when all four of the horse's feet are off the ground.