Xiao Xian (蕭銑) (583–621) was a descendant of the imperial house of the Chinese Liang dynasty, who rose against the rule of the Sui dynasty toward the end of the rule of Emperor Yang of Sui. He tried to revive Liang, and for several years appeared to be successful in doing so, as he, with his capital at Jiangling, ruled over a state that included most of modern Hubei, Hunan, Guangxi, and northern Vietnam. In 621, however, under an attack by the Tang dynasty generals Li Jing and Li Xiaogong, he, not realizing that relief forces were approaching Jiangling, surrendered. He was subsequently taken to the Tang capital Chang'an, where Emperor Gaozu of Tang executed him.

Xiao Xian was a great-grandson of Xiao Cha, Emperor Xuan of Western Liang and a vassal of Western Wei and Northern Zhou, who claimed the Liang imperial title under the support from those states with his capital at Jiangling. His throne passed for two more generations, to Emperor Jing (Xiao Cong), until it was abolished by Emperor Wen of Sui in 587. That year, Xiao Xian's grandfather and Emperor Jing's uncle Xiao Yan (蕭巖) the Prince of Anping and Emperor Jing's brother Xiao Huan (蕭瓛) the Prince of Yixing, believing that the Sui general Cui Hongdu (崔弘度) was about to launch a surprise attack on Jiangling with Emperor Jing away at the Sui capital Chang'an to pay homage to Emperor Wen, surrendered to the Chen dynasty with the people of Jiangling, an act that directly led to Emperor Wen's decision to abolish Western Liang notwithstanding Emperor Jing's submissiveness. In 589, after Emperor Wen conquered Chen, he largely spared Chen officials. However, Xiao Yan and Xiao Huan were executed after they were captured by Yuwen Shu.

As a result of Xiao Yan's death by execution, his family, unlike the rest of the Xiaos, was not treated well by Sui authorities. Xiao Xian himself was poor in his youth, supporting himself and his mother by serving as a scribe. He was known for being filially pious to his mother. During the reign of Emperor Yang, because Emperor Yang's wife Empress Xiao was a sister of Emperor Jing's, her relatives were generally given governmental offices, and Xiao Xian was made the county magistrate of Luochuan (羅川, in modern Yueyang, Hunan).

In 617, several military officers at Baling Commandery (巴陵, roughly modern Yueyang) considered rising against Sui rule. They initially wanted to support one of their own, Dong Jingzhen (董景珍) as leader, but Dong pointed out that he was of a humble lineage and would not be respected by others, but that Xiao Xian was of imperial heritage and would be supported. They therefore sent messengers to Luochuan to report this to Xiao, who then gathered several thousand men. At the same time, the agrarian rebel leader Shen Liusheng (沈柳生) was attacking Luochuan, and Xiao initially could not repel him. However, when Xiao, believing that the act would cause Shen to submit, declared himself the Duke of Liang and replaced all Sui uniforms with Liang ones, Shen submitted. Within five days of Xiao's declaration, he had several tens of thousands of men, and he led them to Baling. Dong sent one of his followers, Xu Deji (徐德基) to greet Xiao, when Shen, believing that his accomplishment would be overshadowed by the contributions of Dong and the others, killed Xu and wanted to detain Xiao. Xiao, in shock, offered to resign, which led Shen to, in fear, beg for forgiveness. Xiao initially pardoned him, but Dong argued that if Xiao did not kill Shen, he could not show the rule of law, and so Xiao changed his mind and allowed Dong to execute Shen. Shen's soldiers fled.

In winter 617, Xiao built a tall altar and burned a wooden pire thereon. He declared himself the Prince of Liang and changed era name to show independence from Sui.

Around the new year 618, Xiao Xian sent his general Su Hu'er (蘇胡兒) to attack another rebel leader, Lin Shihong the Emperor of Chu, who had earlier taken over most of modern Jiangxi and Guangdong. Su captured Lin's major city Yuzhang (豫章, in modern Nanchang, Jiangxi), prompting Lin to retreat from Nankang (南康, in modern Ganzhou, Jiangxi) to Yugan (餘干, in modern Shangrao, Jiangxi).

In summer 618, Xiao took imperial title and established an imperial government with the Liang dynasty governmental structure. He posthumously honored Xiao Cong as Emperor Jing (as Xiao Cong had died with only the Sui title of Duke of Liang), but did not so posthumously honor his grandfather Xiao Yan and father Xiao Gui (蕭璿), honoring Xiao Yan only as Prince Zhonglie of Hejian and Xiao Gui as Prince Wenxian of Hejian. He created seven of his general's princes and sent one of them, Yang Daosheng (楊道生) the Prince of Song to attack Jiangling. After Yang captured Jiangling, Xiao moved his capital from Baling to Jiangling. Meanwhile, the Sui officials in the modern Guangxi and northern Vietnam regions, upon hearing that Emperor Yang had been killed in a coup led by the general Yuwen Huaji in spring 618, largely surrendered to Xiao. Historical records indicate that Xiao's territory went as far east as Jiujiang, as far west as the Three Gorges, as far south as Jiaozhi (交趾, modern Hanoi, Vietnam), and as far north as the Han River, with more than 400,000 regular soldiers under his disposal.

In 619, Xiao made a push to expand his territory to the modern Chongqing and Sichuan region, then held by the Tang dynasty. He sent Yang and Chen Puhuan (陳普環) to attack Tang's Xia Prefecture (峽州, roughly modern Yichang, Hubei), but they were repelled by the Tang general Xu Shao (許紹). In 620, the Tang general Li Xiaogong the Duke of Zhao Commandery attacked Xiao's general Du Ti (闍提) the Prince of Dongping and killed Du.