《史记·十二本纪·秦本纪》
二十七年，秦景公到了晋国，与晋平公订立盟约，不久就背叛了盟约。
二十七年，景公如晋，与平公盟，已而背之。
In the 27th year, Duke Jing of Qin came to the state of Jin and signed an alliance with Duke Ping of Jin, but soon betrayed the alliance.
<s>[INST] Kindly elucidate the central themes in this passage in English: 二十七年，景公如晋，与平公盟，已而背之。 [/INST] In the 27th year, Duke Jing of Qin came to the state of Jin and signed an alliance with Duke Ping of Jin, but soon betrayed the alliance.</s>
Kindly elucidate the central themes in this passage in English: 二十七年，景公如晋，与平公盟，已而背之。
user
In the 27th year, Duke Jing of Qin came to the state of Jin and signed an alliance with Duke Ping of Jin, but soon betrayed the alliance.
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