He was known for having suggested the transition of Tang central government armed forces from being conscription-based to recruitment-based, and for turning the office of the chancellor into a specialized post with strong executive powers.
Zhang Yue was a well-respected literary figure of his time, and was ranked alongside Su Ting (Duke Wenxian of Xu, another of Emperor Xuanzong's chancellors) as the two great writers of the Kaiyuan era.
[3] In his youth, Zhang Yue passed the imperial examinations and received the highest score among the group of people who took the exam at the same time.
[4] During the reign of Wu Zetian (r. 690–705), Zhang Yue was gradually promoted to You Bujue (右補闕), a low-level official at the legislative bureau of government (鳳閣, Fengge).
While serving there, he participated in a project, headed by Li Jiao to create a work known as the Essence of Pearls from the Three Religions (三教珠英, Sanjiao Zhuying)—a compilation of various poetry about Confucianism, Buddhism, and Taoism, in which Wu Zetian's lovers Zhang Yizhi and Zhang Changzong also participated, to give them a legitimate reason to enter the palace.
They therefore falsely accused Wei and the official Gao Jian (高戩) of having said that Wu Zetian was too old and that it was better to support her son and crown prince, Li Xian.
During Emperor Zhongzong's Jinglong era (707-710), his mother died, and he left public service to observe a period of mourning—traditionally three years under Confucian principles, but which were often shortened for officials.
In 710, Emperor Zhongzong died suddenly—a death that traditional historians believed to be a poisoning carried out by his powerful wife Empress Wei and daughter Li Guo'er the Princess Anle, so that Empress Wei could be "emperor" like Wu Zetian and Li Guo'er could be crown princess.
After Emperor Ruizong's return to the throne, Zhang Yue was made Zhongshu Shilang (中書侍郎), the deputy head of the legislative bureau (by now named Zhongshu Sheng (中書省)), as well as the secretary general for the capital prefecture Yong Prefecture (雍州, roughly modern Xi'an, Shaanxi, as Emperor Zhongzong moved the capital back to Chang'an from Luoyang).
Several hundred of people, accused of being complicit with Li Chongfu's plot, were arrested, but it was difficult to adjudicate their guilt or innocence.
Once he returned to Chang'an, Emperor Ruizong thanked him: I know that, as you, Lord, judged this case, that the good were not falsely convicted, and the guilty were not released.
How would this be possible except for your faithfulness and righteousness?At that time, Li Longji was crown prince, and both Zhang Yue and Chu Wuliang (褚無量) served as attending officials in his studies, and he became close to them.
In 711, Zhang was given the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor de facto.
Princess Taiping, who was of high noble status and her wealth, which included: treasure, slaves, livestock, and real estate, was more than the imperial house, and through retired emperor, continued to exert excessive influence on governance.
On July 29,[7] Emperor Xuanzong had Wang Maozhong take 300 soldiers to the imperial guard camp to behead Chang and Li Ci.
Emperor Xuanzong subsequently recalled Zhang from Luoyang to serve as Zhongshu Ling (中書令), the head of the legislative bureau and a post considered one for a chancellor.
For reasons lost to history, he was later demoted to be the prefect of Yue Prefecture (岳州, roughly modern Yueyang, Hunan), and the benefits he was to draw from his fief were suspended.
Thereafter, Zhang was made the secretary general of the more important Jing Prefecture (荊州, roughly modern Jingzhou, Hubei).
Emperor Xuanzong then made him the acting secretary general at Bing Prefecture; the commander of the Tianbing Base (天兵軍, in Bing Prefecture); and chief imperial censor, with directions that he be responsible for editing imperial histories, despite his departure from Chang'an—that is, to have the historical archives delivered to him so that he can edit them while in the army.
In 720, Wang Jun, the commander of the army at Shuofang (朔方, in modern Yinchuan, Ningxia), accused the Pugu (僕固) and Jiadie (name not in Unicode) tribal chieftains of plotting to betray Tang territory to Eastern Tujue, and slaughtered them.
When this was heard by people of Bayegu (拔曵固) and Tongluo (同羅) tribes, who were settled in Zhang's territory, became terrified.
This is time for me to risk death.As a result of Zhang's tour, the Bayegu and Tongluo tribes were calmed and did not create any problems.
Later that year, Zhang was recalled to Chang'an to serve as minister of defense (兵部尚書, Bingbu Shangshu) and chancellor de facto with the designation Tong Zhongshu Menxia Sanpin (同中書門下三品), and he continued to be responsible for editing the imperial histories.
[8]) Soon thereafter, Pei Zhouxian (裴伷先) the commandant at Guang Prefecture (廣州, roughly modern Guangzhou, Guangdong) was accused of corruption, and the chancellor Zhang Jiazhen advocated caning him.
The official Lu Jian (陸堅), believing that the expenses for maintaining Lizheng Institute were unjustified, planned to petition to disband it.
Emperor Xuanzong had Yuan, Cui Yinfu, Wei Kang (韋抗) the minister of justice, and Hu Gui (胡珪) the assistant chief judge of the supreme court, interrogate Zhang.
Emperor Xuanzong, tired of these accusations, in 727, ordered Zhang to retire, Cui to be removed from his post to return home to support his mother, and Yuwen to be demoted to be the prefect of Wei Prefecture (魏州, also in modern Handan).
Even though Zhang was largely retired by this point, it was said that Emperor Xuanzong often sent eunuchs to ask for his suggestions when important matters were to be decided.