 Yelü Bei was twenty @-@ six years old at the time of his father 's death . A polymath , Bei exemplified many of the values of the Chinese aristocracy ; he was an expert in music , medicine , fortune @-@ telling , painting , and writing ( in both Chinese and Khitan ) . He was also an accomplished warrior , leading troops into battle during his father 's conquest of Balhae . After the campaign ended in victory for the Liao in 926 , Emperor Taizu gave Bei command of the conquered territory – – which became known as the principality of Dongdan – – as well as the title of Prince of Dongdan . 
