Xuanwu Gate in Tang Gaozu changed a few years ago.

The change of Xuanwu Gate was a bloody coup staged by Li Shimin, the then king of Qin, and Li Yuan, the second son of Tang Gaozu, on the fourth Gengshen Day in the 9th year of Wude, Tang Gaozu (July 2nd, AD 626), near Xuanwu Gate, the northern palace of Da Nei Palace in Chang 'an, Tang Dou (now Xi, Shaanxi). As a result, Li Shimin killed his eldest brother (then Prince Li) and his fourth brother (then King Li Yuanji of Qi).