《后汉书·列传·党锢列传》
桓帝永寿二年，鲜卑侵犯云中，桓帝听说李膺有才能，于是又征召他作度辽将军。
永寿二年，鲜卑寇云中，桓帝闻膺能，乃复征为度辽将军。
In the second year of Emperor Huan's Yongshou, Xianbei invaded Yunzhong. When Emperor Huan heard that Li Ying was capable, he summoned him to be General Duliao.
<s>[INST] Identify the key themes in this Classical Chinese text and explain them in English: 永寿二年，鲜卑寇云中，桓帝闻膺能，乃复征为度辽将军。 [/INST] In the second year of Emperor Huan's Yongshou, Xianbei invaded Yunzhong. When Emperor Huan heard that Li Ying was capable, he summoned him to be General Duliao.</s>
Identify the key themes in this Classical Chinese text and explain them in English: 永寿二年，鲜卑寇云中，桓帝闻膺能，乃复征为度辽将军。
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In the second year of Emperor Huan's Yongshou, Xianbei invaded Yunzhong. When Emperor Huan heard that Li Ying was capable, he summoned him to be General Duliao.
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