《明史·列传·卷二百零九》
简定于是僭称大号，改纪元为兴庆，定国名于大越，时常出没在翨安、化州的山中，窥伺大军回去后，即出来攻打盘滩的咸子关，扼住三江府的往来孔道，在交州近境为寇。
定乃僣大号，纪元兴庆，国曰大越。出没乂安、化州山中，伺大军还，即出攻盘滩咸子关，扼三江府往来孔道，寇交州近境。
Simpding then usurped the title of emperor, changed the era to Xingqing, and set the country's name as Dayue. He often roamed the mountains of Fei'an and Huazhou, and after the army returned, he came out to attack the Xianziguan of Pantan, strangling the traffic of Sanjiang Prefecture and becoming a robber in the vicinity of Jiaozhou.
<s>[INST] Kindly elucidate the central themes in this passage in English: 定乃僣大号，纪元兴庆，国曰大越。出没乂安、化州山中，伺大军还，即出攻盘滩咸子关，扼三江府往来孔道，寇交州近境。 [/INST] Simpding then usurped the title of emperor, changed the era to Xingqing, and set the country's name as Dayue. He often roamed the mountains of Fei'an and Huazhou, and after the army returned, he came out to attack the Xianziguan of Pantan, strangling the traffic of Sanjiang Prefecture and becoming a robber in the vicinity of Jiaozhou.</s>
Kindly elucidate the central themes in this passage in English: 定乃僣大号，纪元兴庆，国曰大越。出没乂安、化州山中，伺大军还，即出攻盘滩咸子关，扼三江府往来孔道，寇交州近境。
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Simpding then usurped the title of emperor, changed the era to Xingqing, and set the country's name as Dayue. He often roamed the mountains of Fei'an and Huazhou, and after the army returned, he came out to attack the Xianziguan of Pantan, strangling the traffic of Sanjiang Prefecture and becoming a robber in the vicinity of Jiaozhou.
assistant