《三国志·魏书·乌丸鲜卑东夷传》
正始六年，乐浪太守刘茂、带方太守弓遵因为领东氵岁归属句丽，起兵讨伐。
国小，迫于大国之间，遂臣属句丽。
In the 6th year of Zhengshi, Liu Mao, the governor of Lelang, and Gong Zun, the governor of Daifang, launched a military campaign against Goguryeo because it had annexed eastern Bu'nai.
<s>[INST] Kindly elucidate the central themes in this passage in English: 国小，迫于大国之间，遂臣属句丽。 [/INST] In the 6th year of Zhengshi, Liu Mao, the governor of Lelang, and Gong Zun, the governor of Daifang, launched a military campaign against Goguryeo because it had annexed eastern Bu'nai.</s>
Kindly elucidate the central themes in this passage in English: 国小，迫于大国之间，遂臣属句丽。
user
In the 6th year of Zhengshi, Liu Mao, the governor of Lelang, and Gong Zun, the governor of Daifang, launched a military campaign against Goguryeo because it had annexed eastern Bu'nai.
assistant