《辽史·列传·卷二》
后来明宗养子李从珂弑君自立，耶律倍秘密写信给太宗说： 从珂弑君，何不讨伐他？ 
后明宗养子从珂弑其君自立，倍密报太宗曰： 从珂弑君，盍讨之。 
Later Mingzong’s adopted son Li Congke murdered the emperor and declared himself emperor, Yelu Bei secretly wrote a letter to Emperor Taizong and said, “Congke murdered the emperor, why not attack him?”
<s>[INST] Kindly elucidate the central themes in this passage in English: 后明宗养子从珂弑其君自立，倍密报太宗曰： 从珂弑君，盍讨之。  [/INST] Later Mingzong’s adopted son Li Congke murdered the emperor and declared himself emperor, Yelu Bei secretly wrote a letter to Emperor Taizong and said, “Congke murdered the emperor, why not attack him?”</s>
Kindly elucidate the central themes in this passage in English: 后明宗养子从珂弑其君自立，倍密报太宗曰： 从珂弑君，盍讨之。
user
Later Mingzong’s adopted son Li Congke murdered the emperor and declared himself emperor, Yelu Bei secretly wrote a letter to Emperor Taizong and said, “Congke murdered the emperor, why not attack him?”
assistant