Li Chengqian's brother was Li Tai.
Li Chengqian's younger brother was Li Tai. Li Tai was described as a talented and ambitious person who was doted on by his parents. He had gathered scholars to compile the Records of the Land and attacked Li Chengqian in the court, and the relationship between him and Li Chengqian became increasingly tense. Li Chengqian was full of suspicion and fear towards Li Tai. In the end, he was even worried that Li Shimin would make Li Tai the Crown Prince. Thus, there was a tense competitive relationship between Li Chengqian and Li Tai.
Li Chengqian's younger brother was Li Zhi. Li Chengqian was the eldest son of Emperor Taizong of the Tang Dynasty. He was made the crown prince, but was eventually deposed and exiled to Qianzhou. Li Zhi became the crown prince. The search results did not provide more information about their specific relationship and interaction.
Yes, according to the information provided, Li Chengqian was Li Zhi's biological brother. They were the sons of Emperor Taizong and Empress Zhangsun. Li Chengqian was once conferred the title of Crown Prince, but was demoted to a commoner because of his rebellion. In the end, Li Zhi became the Crown Prince and ascended the throne as Emperor Gaozong of Tang Dynasty.
Li Chengqian had a total of three sons, namely Li Xiang, Li Jue, and Li Yi. Li Xiang had held many positions in the Tang Dynasty, including Huaizhou and Ezhou. Li Jue was the grandson of Li Shimin, Emperor Taizong of the Tang Dynasty. He once served as the governor of Ezhou and was posthumously awarded the title of envoy to Qingzhou's military, Qingzhou governor and Zong Zhengqing. As for Doctor Li, there was not much information about him. They only knew that he was born from a concubine and was born between the eighth and twelfth year of Zhenguan.
Li Chengqian had a total of three sons, namely Li Xiang, Li Jue, and Li Yi. Li Xiang served as the governor of Huaizhou during the period of Emperor Taizong of the Tang Dynasty, Li Shimin, and was later granted the title of Governor of Yuezhou and Duke of Huan. Li Jue once served as the governor of Ezhou, and was later posthumously presented as the military envoy of Qingzhou, the governor of Qingzhou, and Zong Zhengqing. As for the specific situation of Doctor Li, the search results did not provide any relevant information.