Guangwu claims the throne as Emperor of China, restoring the Han dynasty after the collapse of the short-lived Xin dynasty.

AD 25 (XXV) was a common year starting on Monday of the Julian calendar. At the time, it was known as the Year of the Consulship of Lentulus and Agrippa. The denomination AD 25 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Emperor Guangwu of Han, born Liu Xiu (劉秀), courtesy name Wenshu (文叔), was a Chinese monarch. He served as an emperor of the Han dynasty by restoring the dynasty in AD 25, thus founding the Eastern Han dynasty. He ruled over parts of China at first since his dynasty was formed through rebellion against the short-lived Xin dynasty, and through suppression and conquest of regional warlords, the whole of China proper was consolidated by the time of his death in AD 57. During his reign, Taoism was made the official religion of China, and the Chinese folk religion began to decline.

Throughout Chinese history, "Emperor" was the superlative title held by the monarchs of imperial China's various dynasties. In traditional Chinese political theory, the emperor was the "Son of Heaven", an autocrat with the divine mandate to rule all under Heaven. Emperors were worshiped posthumously under an imperial cult. The lineage of emperors descended from a paternal family line constituted a dynasty, and succession in most cases theoretically followed agnatic primogeniture. The emperor of China was an absolute monarch.

The Han dynasty was an imperial dynasty of China established by Liu Bang and ruled by the House of Liu. The dynasty was preceded by the short-lived Qin dynasty (221–206 BC) and a warring interregnum known as the Chu–Han Contention (206–202 BC), and it was succeeded by the Three Kingdoms period (220–280 AD). The dynasty was briefly interrupted by the Xin dynasty (9–23 AD) established by the usurping regent Wang Mang, and is thus separated into two periods—the Western Han and the Eastern Han (25–220 AD). Spanning over four centuries, the Han dynasty is considered a golden age in Chinese history, and had a permanent impact on Chinese identity in later periods. The majority ethnic group of modern China refer to themselves as the "Han people" or "Han Chinese". The spoken Chinese and written Chinese are referred to respectively as the "Han language" and "Han characters".