An empress is a woman who rules an empire, or the wife of an emperor. An empire is a group of countries or territories under one ruler's control, usually spanning vast distances and including many different peoples and cultures.

Some empresses ruled in their own right, commanding armies, making laws, and shaping history. Empress Wu Zetian of China rose from humble beginnings to become the only woman to rule China as emperor in her own name, governing effectively for decades. Catherine the Great transformed Russia into a major European power through military conquests and cultural reforms. These women weren't just figureheads: they wielded real power and left lasting legacies.

Other empresses gained their title through marriage to an emperor. Even without ruling directly, many influenced their husbands' decisions or ruled as regents when emperors were too young or unable to govern. Empress Theodora of Byzantium, though married to Emperor Justinian, was his close advisor and helped shape laws that protected women's rights.

While kings and queens rule kingdoms, emperors and empresses rule empires, which are typically larger and more diverse. Today, only Japan still has an emperor and empress, though the titles are ceremonial rather than political.