sentences:  The kingdom of Heung-yo gathered the attention of numerous Balhae people, and flourished until 1030 AD, when the Liao sent an army to conquer and destroy the kingdom.Dae Yeon-rim's Heung-yo kingdom was pushed back to its capital city, and continued to fight the Liao until a traitorous general opened the city gates, allowing the enemy to overwhelm the city defenses.After only a year, Dae Yeon-rim's kingdom fell at the hands of one of his own subcommanders.