In the winter of 617, Li Yuan occupied Chang'an while Emperor Yang of Sui was still alive. This action marked the beginning of a new era for China after decades of fragmentation under the collapsing Sui dynasty. Li Yuan, previously Duke of Tang and governor of Taiyuan, possessed both prestige and military experience that allowed him to seize power during the chaos. His daughter Princess Pingyang raised and commanded her own troops, adding to his growing strength. On the 18th of June 618, news arrived that General Yuwen Huaji had murdered Emperor Yang. Li Yuan immediately declared himself emperor of the newly founded Tang dynasty.
Li Shimin, later known as Emperor Taizong, played a crucial role in establishing Tang control over vast territories. He commanded troops since age eighteen and demonstrated exceptional prowess with bow, arrow, sword, and lance. In the 28th of May 621, he defeated Dou Jiande at Luoyang during the Battle of Hulao against a numerically superior army. The Xuanwu Gate Incident on the 2nd of July 626 saw Li Shimin ambush and kill two of his brothers: crown prince Li Jiancheng and Prince Li Yuanji. Shortly thereafter, his father abdicated in his favor, allowing Li Shimin to ascend the throne.
Emperor Taizong's reign extended Tang influence far beyond previous dynastic borders. In 630, Tang armies captured areas of the Ordos Desert from the Turks. On the 11th of June 631, an embassy bearing gold and silk successfully freed eighty thousand Chinese men and women who had been enslaved by northern frontier tribes. By 649, when Emperor Gaozong succeeded Taizong, the Tang Empire controlled territory rivaling that of the Han dynasty. Military campaigns continued under both emperors, destroying the Eastern Turkic Khaganate after capturing its ruler Illig Qaghan.
Wu Zetian Usurpation
Entering Emperor Gaozong's court as a lowly consort, Wu Zetian ultimately acceded to the highest position of power in 690. When Emperor Gaozong suffered a stroke in 655, she began making many of his court decisions for him while sitting behind a screen discussing affairs with councillors who took orders from her. Her eldest son, the crown prince, suddenly died in 675 after advocating policies opposed by Empress Wu. Many suspected he was poisoned by her hands.
In 683, Emperor Gaozong died and was succeeded by Emperor Zhongzong, his eldest surviving son by Wu. After only six weeks on the throne, Zhongzong was deposed by Empress Wu in favor of his younger brother, Emperor Ruizong. This provoked a group of Tang princes to rebel in 684, but Wu's armies suppressed them within two months. She proclaimed the Tianshou era of Wu Zhou on the 16th of October 690, three days later demoting Emperor Ruizong to crown prince.
A palace coup on the 20th of February 705 forced Empress Wu to yield her position on February 22. The next day, her son Zhongzong was restored to power; the Tang was formally restored on March 3. To legitimize her rule, she circulated a document known as the Great Cloud Sutra, which predicted that a reincarnation of the Maitreya Buddha would be a female monarch. She even introduced numerous revised written characters for the language, though they reverted to original forms after her death.
Her most significant legacy involved diminishing the hegemony of the Northwestern aristocracy. This allowed people from other clans and regions of China to become more represented in Chinese politics and government. Her reign demonstrated how political maneuvering could reshape imperial authority structures.