Research published in the journal Science has helped to explain the climate conditions behind Genghis Khan’s rise to power. Through examining the inside of old trees from lava fields in Mongolia, researchers were able to note an abundance of rainfall during the period that the infamous emperor first began to conquer surrounding lands.

Genghis Khan was said to be born in Mongolia around 1155 CE. Originally named “Temujin,” Genghis Khan united several tribes to build an army of more than 20,000 soldiers by the age of 20. Temujin was able to take out rival tribes through strong military tactics and, as the study points out, “conquer more territory in 25 years than the Romans did in 400.” Tribal groups in Mongolia bestowed Temujin the title of “Genghis Khan,” which translates to “universal ruler.”

Researchers were able to study old trees located near the dormant Khorgo Volcano in Mongolia. A volcanic eruption that occurred 8,000 to 9,000 years ago left lava covering the surrounding field and plant-life. Because of this eruption, the “lava-stressed” trees became very sensitive to changes in moisture. By studying the rings of these trees, researchers were able to study the moisture fluctuations throughout this period. Based on the findings, researchers were able to conclude that there was heavy rainfall from the period of 1211 to 1230 CE, when Khan was beginning his conquest.

While certainly Genghis Khan’s military prowess was one of his strongest assets, this data shows that he also benefited from a convivial climate producing abundant vegetation to allow livestock to also flourish.

This study is only the beginning of new research into linking climate changes with past history. Other research includes a study from the University of Washington, which looks to take sediment samples from the bottom of Lake Terkhiin Tsagaan to determine the number of livestock that have utilized the lake over the years.