Ghengis Kahn was born in 1162
in 1206 he had united all the Mongol tribes as one and created the Mongol Empire.
In 1215 Ghengis had conquered Yanjing (Beijing) which was the capital of the Jin Empire, a great enemy of the Mongols. In 1218, he had conquered he had conquered all the way up to the Caspian Sea - Persian Gulf - Arabian Sea.
In 1220 the Khwarizmian Empire (A Middle-Eastern Muslim empire) was invaded by the Mongols.
While Genghis gathered his forces in Persia and Armenia, a detached force of 40,000 troops of Batu Khan commanded by Subutai pushed deep into Armenia and Azerbaijan. Batu destroyed Georgian crusaders, sacked the Genoese trade-fortress of Kaffa in Crimea, and stayed the winter near the Black Sea.
Mongol Empire in 1227 at Genghis' death
after his death his son Ögedei Khan took charge of the empire. By 1279 Ogedei had conquered all of China.
Then, in the late 1230s, the Mongols under Batu Khan invaded Russia and Volga Bulgaria
By 1295, the Mongol Empire has disintegrated into smaller seperate empires or had been invaded or re-claimed.
Greatest extent of the Mongol Empire: