Why The Ancient Mongol Army Retreated From Europe

It could have been the most devastating invasion of Europe after Attila the Hun, but the attack by the Golden Horde, led by a grandson of Genghis Khan, ended abruptly in AD 1242 with their unexplained retreat from Hungary.

Researchers now think they’ve figured out why the all-conquering horsemen turned tail – it was the mud.

A detailed analysis of climate data, including tree rings, combined with contemporary accounts led them to conclude that unusually wet, marshy Spring conditions forced the Mongols to withdraw.

Whether the retreat saved Europe from Islamic conquest, thus preventing the destruction of both Christendom and Western Civilisation, is unknowable.

But the possibility that microclimatic changes could have turned the course of major historical events is now firmly on the academic table.

Only recently did scientists and historians combine forces to look at the long-term effects of weather on human events, specifically the rise of Genghis Khan’s empire, says Professor Nicola Di Cosmo at the Institute for Advanced Study in Princeton.

The Mongol empire built by Genghis Khan and his descendants extended from China to Russia. (National Geographic, The Forbidden Tomb of Genghis Khan)

Now Prof Di Cosmo and Swiss climatologist Dr Ulf Buentgen argue in Nature, Scientific Reports that a particularly harsh winter with heavy snowfall initially helped the Horde cross the frozen Danube.

But the subsequent thaw turned the Mongols’ great military advantages, the speed and manoeuvrability of their cavalry, into liabilities. The horses became mired in muck, and good pasture for them disappeared beneath floodwaters.

The Mongol Empire’s expansion had begun after Genghis Khan (1162-1227) became the nomads’ undisputed ruler in 1206. He soon led campaigns into China and Central Asia, possibly aided by wetter conditions that would have increased agricultural production on the steppes of his homeland.

His son, Ogodei Khan (1229-1241) completed the conquest of northern China then sent his forces West to attack Russia, leading to the capture of Kiev in 1240. The obvious next move was to cross the Carpathians, an arc of mountains that protect Hungary’s northern and eastern flanks.

Batu, one of the Great Khan’s grandsons, led some 130,000 soldiers in a co-ordinated attack across more than one mountain pass, defeating the Poles at Liegnitz on 9 April and the Hungarians at Mohi two days later. Bela IV, the King of Hungary, fled to Trogir, a town on the Dalmatian coast then controlled by Venice.

In early 1242, the Mongols crossed the frozen Danube. It was long thought that they left again just two months later because Batu needed to return to Karakorum for the election of a new khan after his uncle’s death. But he never went all the way, stopping in Russia and consolidating the Horde’s power there.

Other historians have speculated that the invasion was just a raid, and the Mongols never intended to stay, or that the countryside could not support them in the long run, or that the defences were just too strong to overcome.

But Di Cosmo and Buentgen note that the trouble with the region’s walled cities, such as Székesfevehérvár (then the Hungarian capital) and Trogir, was that they were surrounded by waterlogged ground.

“While stone fortresses offered greater resistance, the Mongol failure is explicitly attributed in the [contemporary] sources to swampy terrain,” the authors said. “It is possible that these conditions made it much more difficult to operate siege engines and to keep a cavalry force in the surrounding areas.

“Moreover, the early spring thaw may have severely reduced the amount of grazing land, with horses already weakened by the winter.”

Source: forbes