It is speculated that when Jiang Zemin was close to the end of his term for his age, he put many members of the Crown Prince Party into important positions to appeal to senior leaders of the CCP and win their support for his continued influence. There is a trend towards members of the Crown Prince Party taking over power step by step. Of these, Yu Zhengsheng, son of Huang Jing, former mayor of Tianjin, was already a member of the powerful politburo of the CCP; Wang Qishan, son-in-law of Yao Yilin (former vice premier and member of politburo), mayor of Beijing; Xi Jinping, Bo Xilai, Zhou Xiaochuan, son of Zhou Jiannan (former minister of the First Machinery Ministry and Jiang Zemin’s former boss), governor of the People's Bank of China, have also occupied important positions since the 17th Party Congress.