Chengdu, Sichuan), and as the titular commandant at Yi Prefecture was Emperor Taizong's young son Li Ke the Prince of Shu, Gao was effectively commandant. It was said that while serving at Yi Prefecture, Gao disabused the people of superstitions that led them not to attend to their parents when their parents were ill, improved irrigation, and encouraged learning. In 631, Gao was recalled to the capital to serve as the minister of civil service affairs, and was created the greater title of Duke of Xu. One of his sons was also created a lesser duke. When Emperor Gaozu died in 635, Gao was in charge of building Emperor Gaozu's tomb, and was rewarded after the projet was completed. In 637, as part of Emperor Taizong's scheme to bestow prefectures on his relatives and great generals and officials as their permanent domains, Gao's title was changed to Duke of Shen, and he was given the post of a prefectural prefect for his heirs to inherit. Soon, however, with many objections to the system, the strongest of which came from Zhangsun Wuji, Emperor Taizong cancelled the scheme, although Gao's title remained Duke of Shen. Sometime before 638, Emperor Taizong, disgusted with the traditional noble clans of Cui, Lu, Li, and Zheng and believing that they were abusing their highly honored names, commissioned Gao, Wei Ting (韋挺), Linghu Defen, and Cen Wenben to compile a work later to be known as the Records of Clans (氏族志), with the intent of dividing the clans into nine classes based on their past contributions, good deeds, and ill deeds. In an initial draft that Gao submitted, he nevertheless ranked the branch of the Cui clan that the official Cui Min'gan (崔民幹) belonged to as the highest, a decision that Emperor Taizong rebuked, as he pointed out that Gao was merely again looking at tradition and not the recent contributions. He therefore personally intervened in revising the work, reducing Cui's clan to the third class. However, after the work was completed in 638, Emperor Taizong nevertheless rewarded Gao for compiling the work. In fall 638, he made Gao Pushe (僕射), a head of the important executive bureau of the government and also a post for a chancellor. In 641, when Emperor Taizong visited the eastern capital Luoyang, he left his crown prince Li Chengqian in charge of Chang'an, but had Gao serve as his assistant and