Li Chengqian
In 641, When Emperor Taizong visited the eastern capital Luoyang, Li Chengqian was in charge of Chang'an, assisted by the chancellor Gao Shilian (his granduncle). Around that time, Li Chengqian had gathered a group of guards who served as his personal assassins, and when he grew angry at the earnest urgings by Yu Zhining, he sent his assassins Zhang Shizheng (張師政) and Gegan Chengji (紇干承基) to kill Yu, although Zhang and Gegan, when they saw that Yu was observing a mourning period for his mother, relented and did not kill Yu. Meanwhile, in 642, with Li Tai engaging many scholars on staff, Emperor Taizong had increased Li Tai's stipend so much that it exceeded Li Chengqian's. The official Chu Suiliang, whose advice Emperor Taizong usually listened to, advised against this, believing that this would bring conflict. Instead, Emperor Taizong removed all limits on Li Chengqian's spending, causing Li Chengqian to be wasteful. When Zhang advised against wastefulness, Li Chengqian became so displeased that he sent servants to attack Zhang with large whips, almost killing him. With Emperor Taizong's favors for Li Tai apparent, there began to be a faction that supported Li Chengqian and a faction that supported Li Tai at court. In order to quell the speculations about Li Tai's replacing Li Chengqian, Emperor Taizong made the honored chancellor Wei Zheng Li Chengqian's senior advisor, but this failed to end the rumors. The rumors also continued to persist even after Emperor Taizong publicly declared in spring 643 that even if Li Chengqian died (as Li Chengqian's foot illness—the historical accounts did not specify what kind of illness—was well-known among the officials), Li Chengqian's son Li Xiang (李象) would inherit the throne, not another prince.