Complex sentence: The Mongols had acquired the technique of distilling "Arak" from the during their invasion of Central Asia and the Middle East around 1256, it was subsequently introduced to Koreans and distilleries were set up around the city of Kaesong.
Split into simpler sentences: The Mongols had acquired the technique of distilling "Arak" from the during their invasion of Central Asia and the Middle East around 1256. It was subsequently introduced to the Koreans, and distilleries were set up around the city of Kaesong.