The Mongol invasions and conquests took place during the 13th and 14th centuries, creating history's largest contiguous empire: the Mongol Empire, which by 1300 covered large parts of Eurasia. Historians regard the Mongol devastation as one of the deadliest episodes in history. In addition, Mongol expeditions may have spread the bubonic plague across much of Eurasia, helping to spark the Black Death of the 14th century.

The Mongol Empire developed in the course of the 13th century through a series of victorious campaigns throughout Asia, reaching Eastern Europe by the 1240s. In contrast with later "empires of the sea" such as European colonial powers, the Mongol Empire was a land power, fueled by the grass-foraging Mongol cavalry and cattle.Thus most Mongol conquest and plundering took place during the warmer seasons, when there was sufficient grazing for their herds. The rise of the Mongols was preceded by 15 years of wet and warm weather conditions from 1211 to 1225 that allowed favourable conditions for the breeding of horses, which greatly assisted their expansion.

As the Mongol Empire began to fragment from 1260, conflict between the Mongols and Eastern European polities continued for centuries. Mongols continued to rule China into the 14th century under the Yuan dynasty, while Mongol rule in Persia persisted into the 15th century under the Timurid Empire. In India, the later Mughal Empire survived into the 19th century.

Central Asia
Genghis Khan forged the initial Mongol Empire in Central Asia, starting with the unification of the nomadic tribes Merkits, Tatars, Keraites, Turks, Naimans and Mongols. The Uighur Buddhist Qocho Kingdom surrendered and joined the empire. He then continued expansion via conquest of the Qara Khitai and the Khwarazmian dynasty.

Large areas of Islamic Central Asia and northeastern Iran were seriously depopulated, as every city or town that resisted the Mongols was destroyed. Each soldier was given a quota of enemies to execute according to circumstances. For example, after the conquest of Urgench, each Mongol warrior – in an army of perhaps two tumens (20,000 troops) – was required to execute 24 people, or nearly half a million people per said army.

Against the Alans and the Cumans (Kipchaks), the Mongols used divide-and-conquer tactics by first warning the Cumans to end their support of the Alans, whom they then defeated, before rounding on the Cumans. Alans were recruited into the Mongol forces with one unit called "Right Alan Guard" which was combined with "recently surrendered" soldiers. Mongols and Chinese soldiers stationed in the area of the former Kingdom of Qocho and in Besh Balikh established a Chinese military colony led by Chinese general Qi Kongzhi (Ch'i Kung-chih).

During the Mongol attack on the Mamluks in the Middle East, most of the Mamluk military was composed of Kipchaks, and the Golden Horde's supply of Kipchak fighters replenished the Mamluk armies and helped them fight off the Mongols.

Hungary became a refuge for fleeing Cumans.

The decentralized, stateless Kipchaks only converted to Islam after the Mongol conquest, unlike the centralized Karakhanid entity comprising the Yaghma, Qarluqs, and Oghuz who converted earlier to world religions.

The Mongol conquest of the Kipchaks led to a merged society with a Mongol ruling class over a Kipchak-speaking populace which came to be known as Tatar, and which eventually absorbed Armenians, Italians, Greeks, and Goths on the Crimean peninsula to form the modern day Crimean Tatar people.

East Asia
Genghis Khan and his descendants launched progressive invasions of China, subjugating the Western Xia in 1209 before destroying them in 1227, defeating the Jin dynasty in 1234 and defeating the Song dynasty in 1279. They made the Kingdom of Dali into a vassal state in 1253 after the Dali King Duan Xingzhi defected to the Mongols and helped them conquer the rest of Yunnan, forced Korea to capitulate through nine invasions, but failed in their attempts to invade Japan, their fleets scattered by kamikaze storms.

The Mongols' greatest triumph was when Kublai Khan established the Yuan dynasty in China in 1271. The dynasty created a "Han Army" (漢軍) out of defected Jin troops and an army of defected Song troops called the "Newly Submitted Army".

The Mongol force which invaded southern China was far greater than the force they sent to invade the Middle East in 1256.

The Yuan dynasty established the top-level government agency Bureau of Buddhist and Tibetan Affairs to govern Tibet, which was conquered by the Mongols and put under Yuan rule. The Mongols also invaded Sakhalin Island between 1264 and 1308. Likewise, Korea (Goryeo) became a semi-autonomous vassal state of the Yuan dynasty for about 80 years.

North Asia
By 1206, Genghis Khan had conquered all Mongol and Turkic tribes in Mongolia and southern Siberia. In 1207 his eldest son Jochi subjugated the Siberian forest people, the Uriankhai, the Oirats, Barga, Khakas, Buryats, Tuvans, Khori-Tumed, and Yenisei Kyrgyz. He then organized the Siberians into three tumens. Genghis Khan gave the Telengit and Tolos along the Irtysh River to an old companion, Qorchi. While the Barga, Tumed, Buriats, Khori, Keshmiti, and Bashkirs were organized in separate thousands, the Telengit, Tolos, Oirats and Yenisei Kirghiz were numbered into the regular tumens Genghis created a settlement of Chinese craftsmen and farmers at Kem-kemchik after the first phase of the Mongol conquest of the Jin dynasty. The Great Khans favored gyrfalcons, furs, women, and Kyrgyz horses for tribute.

Western Siberia came under the Golden Horde. The descendants of Orda Khan, the eldest son of Jochi, directly ruled the area. In the swamps of western Siberia, dog sled Yam stations were set up to facilitate collection of tribute.

In 1270, Kublai Khan sent a Chinese official, with a new batch of settlers, to serve as judge of the Kyrgyz and Tuvan basin areas (益蘭州 and 謙州). Ogedei's grandson Kaidu occupied portions of Central Siberia from 1275 on. The Yuan dynasty army under Kublai's Kipchak general Tutugh reoccupied the Kyrgyz lands in 1293. From then on the Yuan dynasty controlled large portions of Central and Eastern Siberia.

Eastern and Central Europe
The Mongols invaded and destroyed Volga Bulgaria and Kievan Rus', before invading Poland, Hungary, Bulgaria, and other territories. Over the course of three years (1237–1240), the Mongols razed all the major cities of Russia with the exceptions of Novgorod and Pskov.

The Mongol invasions displaced populations on a scale never seen before in central Asia or eastern Europe. Word of the Mongol hordes' approach spread terror and panic. The violent character of the invasions acted as a catalyst for further violence between Europe's elites and sparked additional conflicts. The increase in violence in the affected eastern European regions correlates with a decrease in the elite's numerical skills, and has been postulated as a root of the Great Divergence.

South Asia
From 1221 to 1327, the Mongol Empire launched several invasions into the Indian subcontinent. The Mongols occupied parts of Punjab region for decades. However, they failed to penetrate past the outskirts of Delhi and were repelled from the interior of India. Centuries later, the Mughals, whose founder Babur had Mongol roots, established their own empire in India.

Death Toll
Due to the lack of contemporary records, estimates of the violence associated with the Mongol conquests vary considerably. Not including the mortality from the Plague in Europe, West Asia, or China it is possible that between 20 and 57 million people were killed between 1206 and 1405 during the various campaigns of Genghis Khan, Kublai Khan, and Timur. The havoc included battles, sieges, early biological warfare, and massacres.

Timeline
1207 conquest of Siberia
1211–1234 conquest of Jin dynasty
1216–1220 conquest of Central Asia and Eastern Persia
1216–1218 conquest of the Qara Khitai
1219–1220 conquest of Khwarazm
1256 capture of Alamut
1220–1223, 1235–1330 invasions of Georgia and the Caucasus
1220–1224 invasion of the Cumans
1222–1327 Mongol invasions of India
1223–1236 invasion of Volga Bulgaria
1225–1227 conquest of Western Xia
1231–1259 invasion of Korea
1233 conquest of Eastern Xia
1235–1279 conquest of Song dynasty
1222, 1236–1242 Mongol invasion of Europe
1236–1242 invasion of Rus
1237–1238 invasion of eastern and northern Rus'
1239–1240 invasion of southern and western Rus'
1237–1242 invasion of Cumania
1241–1242 invasion of Moldavia and Wallachia
1238–1239 invasion of Circassia
1238–1239 invasion of Chechnya
1241 invasion of Poland and Bohemia;
1241 Battle of Legnica
1241 invasion of Hungary
1241 Battle of Mohi
1241 invasion of Austria and Northeast Italy
1241–1242 invasion of Croatia
1242 invasion of Bulgaria and Serbia
1240–1241 invasion of Tibet
1241–1244 invasion of Anatolia
1244–1265 invasion of Dali Kingdom
1251–1259 invasion of Persia, Syria and Mesopotamia
1253–1256 invasion of Yunnan
1253–1256 Mongol campaign against the Nizaris
1257, 1285, 1287 invasions of Vietnam
1258 invasion of Baghdad
1258–1260 invasion of Halych-Volhynia, Lithuania and Poland
Sack of Sandomierz
1260 Battle of Ain Jalut
1260 Mongol raid against Syria
1264–1265 raid against Bulgaria and Thrace
1264–1308 invasion of Sakhalin Island
1271 raid against Syria
1274, 1281 invasions of Japan
1274 raid against Bulgaria
1275, 1277 raids against Lithuania
1277 battle of Abulustayn
1277 invasion of Myanmar
1281 invasion of Syria
1284–1285 invasion of Hungary
1285 raid against Bulgaria
1283 invasion of Khmer Empire
1287 invasion of Myanmar
1287–1288 invasion of Poland
1293 invasion of Java
1299 invasion of Syria
1300 Mongol invasion of Myanmar
1300 Mongol invasion of Syria
1303 Invasion of Syria
1307 Mongol invasion of Gilan
1312 Mongol invasion of Syria
1324, 1337 Tatar raids against Thrace
1337, 1340 Ruthenian-Tatar raids against Poland