In 926 he seized power by a coup d'état when a mutiny called the Xingjiao Gate Incident killed Li Cunxu, and ruled with both discipline and compassion for the next seven years.

Li Siyuan was born with the Shatuo name of Miaojilie in 867 in Yingzhou (應州; present-day Ying County, Shanxi), without a surname like his nomadic Turkic ancestors.

In 880, they were defeated by the joint forces of military governor Li Zhuo (李琢) and Tuyuhun chieftain Helian Duo,[2] and the Shatuo army fled northward to the Yin Mountains where they sought refuge with a Mohe tribe.

[10] In 883, Li Keyong was made the military governor (Jiedushi) of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi) after a major victory against Qi.

At night, a completely drunk Li Keyong was ambushed in his lodging by Zhu's assassins who had already placed felled trees, fences and wagons to block the exits.

[2] In 890, Li Keyong's old enemy Helian Duo attacked northern Hedong with his Xianbei tribesmen, reinforced by Tibetan and Yenisei Kirghiz troops.

[12] A couple of years later, Li Siyuan demonstrated his military leadership again by leading a force to quell a rebellion, capturing its leader Wang Bian (王弁).

Once at a gathering, generals started bragging about their accomplishments, when Li Siyuan interrupted and spoke slowly: "You sirs, use your mouths to attack enemies.

As Li Keyong, already the Prince of Jin by title, personally removed the clothing and medicated the wounds with alcohol, he remarked with pride: "My son is such an extraordinary man!"

Shortly after, Zhu sent his general Kang Huaizhen (康懷貞) to command an army to attack Jin's Zhaoyi Circuit (昭義, headquartered in modern Changzhi, Shanxi), then under Li Sizhao's governance.

[15] In 912, Li Cunxu launched a major campaign, intending to destroy the Yan state ruled by Liu Shouguang, with Zhou in command of the overall operations.

As part of the campaign, Li Siyuan was in charge of attacking Ying Prefecture (瀛州, in modern Cangzhou, Hebei), and he was successful in getting its prefect, Zhao Jing (趙敬), to surrender.

Li Siyuan first attacked Wu Prefecture (武州, in modern Zhangjiakou, Hebei), and its prefect Gao Xinggui (高行珪) surrendered.

However, at the same time as his declaration, the Later Tang state was facing several serious threats that caused its subjects to be distressed about its prospects — the Khitan Empire was continuing to harass Lulong Circuit; Later Liang had just recently seized Wei Prefecture (衛州, in modern Puyang, different than the Wei Prefecture referred to above); and Zhaoyi Circuit, previously governed by Li Sizhao but under the control of his son Li Jitao after his battlefield death during the Zhao campaign, had just rebelled against Later Tang and pledged allegiance to Later Liang.

[20] In spring 924, Khitan forces made an incursion into Lulong territory, going as deep into Later Tang as Waqiao Pass (瓦橋關, in modern Baoding).

Kang Yanxiao subsequently rebelled, and while his rebellion was quickly suppressed, the soldiers' dissensions continued, particularly because at that time, the Luoyang region was stricken with famine, leading to many rumors.

He initially wanted to return to Chengde and then submitting a petition begging forgiveness for being unable to properly rein in his troops, but Li Shaozhen and An Chonghui pointed out that he would then be vulnerable to accusations of occupying the land for his own benefit.

(Li Cunxu's chancellors Doulu Ge and Wei Yue were initially retained as well, but were subsequently removed and exiled after they were accused of corruption.)

The ones that An was particularly concerned about were Meng Zhixiang the military governor of Xichuan Circuit (西川, headquartered in modern Chengdu, Sichuan) and Dong Zhang the military governor of Dongchuan Circuit (東川, headquartered in modern Mianyang, Sichuan) — whose territories were the ones captured earlier from Former Shu — because Dong was considered a strong-willed general and Meng was married to Li Cunxu's cousin (or sister).

Li Siyuan, initially believing in Wang Jianli, decided to send An and Zhang out of the capital to serve as military governors, but after Zhu Hongzhao defended An, did not do so.

However, as at that time Zheng Jue requested retirement, Li Siyuan kept Wang Jianli at the imperial government to serve as chancellor and the director of the three financial agencies.

His oldest biological son Li Congrong was, by this time, serving as the military governor of Hedong, and was considered the likely heir, but he was said to be arrogant and inattentive to governance.

However, Li Congrong did not accept the advice, and instead was listening to his close associate Yang Siquan (楊思權), who was advocating that he gather officers around him to be able to react with force if he were bypassed.

An had Wu put to death, and then persuaded Li Siyuan to issue an edict ordering Qian to retire as Taishi (太師) and stripping him of his other posts.

Consort Wang had a liking for luxurious clothing, and An Chonghui tried to correct her behavior, citing to her the example of Li Cunxu's hoarding wife Empress Liu.

Zhu Hongzhao, who was previously a close associate of An's and who was then the military governor of Fengxiang Circuit (鳳翔, headquartered in modern Baoji, Shaanxi), also submitted a petition accusing An of planning to take over Shi's army.

As Li Siyuan suffered a minor stroke at that time, that illness, coupled with the failure of the Dingnan campaign, led to many rumors in the army.

However, Li Congrong perceived the situation differently — and he soon went to see his father, stating, "I had heard that evil people had asked that I, your subject, be made the crown prince.

Fearing that the throne would go to his younger brother Li Conghou, whom he felt was a more favored and worthy son, he decided to act first and seize power militarily.

[6] When chancellor Feng Dao and other courtiers visited him, the dying emperor uttered in tears, "I am embarrassed to meet you, my subjects, under such tragic family conditions."