On May 17, 645, the flames of the fall of the Riaotung fortress were seen in the northeastern part of Baekam the fortress. The next time, Master of Castle Son Dae-eum who believed to be Baekam Fortress, was terrified, and sent a man to Emperor Tang Taejong to reserve surrender. Son Dae-eum, who thought only of his own safety, had a strong desire for personal survival, and it was fear that dominated his head. On May 29, Asanasama, a royal family of Trük, was bowed while approaching the wall of Baekam Fortress with troops. Asanasama led the Trük cavalry in Goguryeo. The same was true of Asanasai, Asanachung and Gipsil, who also fought together. Gyepilharyuk Army led cavalry consisting of the Western Trük, Senbi, Tibetian, and Iranians. The battleground was a race showroom. Ogol Fortress sent 10,000 Goguryeo troops to save Baekam Fortress. A battle was fought between nomadic cavalry and Goguryeo cavalry. Gyepilharyuke was surrounded by Goguryeo troops, and as the siege narrowed, nomadic cavalry died. In Goguryeo War, Nomadic cavalry played a pivotal role in the Tang army which has a lot of acidity. Nomads living in harsh conditions basically had the art of shooting bows and swinging spears on swaying horses. It was fundamentally different from dealing with weapons on fixed ground. They were like high-performance interceptors. Without them, Chinese soldiers could not defend the supply route, encircle Goguryeo's fortresses, or carry the siege planes that smashed the fortress. One of the important functions of the castle is the sit-in, but it is a desperate stage of siege. The isolated castle was often attacked by an air force and eventually fell. In order for the situation not to go that far, cavalry must support it. There may be a limit to the cavalry of the castle itself under attack. Therefore, we need to get support from nearby castles. It is Army of Ogolseong Fortress The victorious Goguryeo cavalry raised the morale of Baekam Fortress. The people of the castle showed hope that they could protect their living quarters. Son Dae-eum also regretted. Then the angry emperor allowed the plunder after the fall of the fortress. Gyepilharyuke, who was alive but angry, was dispatched again (May 29). His followers also reportedly broke Goguryeo cavalry from Ogolseong Fortress. From the point of gaining the upper hand in cavalry, the Tang army was able to move the siege to the city of Baengam on 30 May. Catapult hit the fortress. Stones and arrows pour into the castle. The rising momentum of the Tang army also increased. ju Son Dae-eum's heart leaned back toward surrender. He sent a secret agent to ask the emperor to surrender again. Tang's flag hung over the castle. Goguryeo soldiers saw it and stopped resistance. Baekamseong Fortress has fallen. The emperor decided to ban looting and reward soldiers at his own expense. He had to show Mercy to the Goguryeo people. We do not know the name of the Master of Liaodong ㆍGemo Castle who died while guarding the castle. The Master of Anshi Castle who defeated the emperor, did not make a name in history. However, Son Dae-eum, who sold off the castle, was recorded. tress.