Abstract:
After Baiji was set as the southern military base, in the first year of Longshuo (661), under the order of Emperor Gaozong, Su Dingfang led 35 armies and jointly attacked Koguryo with Silla from the southern and northern sides.Although they besieged the capital city of Pyongyang for half a year, they finally returned without accomplishing anything.The reasons lie in four aspects.Firstly, the remaining Tang troops in Baiji were trapped, making it difficult to effectively collaborate with Su Dingfang’s expeditionary force.Secondly, there was no internal conflict in Koguryo, leaving no opportunity for Su Dingfang.Thirdly, the domestic Tie Le rebellion intervened in Gaozong’s strategy of jointly attacking Koguryo from the southern and northern sides.Fourthly, from lunar December, the Tang expeditionary force suffered hunger and cold, finally failing in their attack.
