viceroy
A ruler who governs a place for a king or queen.
A viceroy is a person who governs a country or province as the representative of a monarch. The word literally means “in place of the king”: when a king or queen ruled an empire that stretched across distant lands, they couldn't be everywhere at once, so they appointed viceroys to rule in their name.
Viceroys wielded enormous power. They commanded armies, collected taxes, made laws, and settled disputes, almost as if they were monarchs themselves. But unlike kings, viceroys could be replaced if the monarch back home was displeased with their performance.
The British Empire famously appointed viceroys to govern India for nearly a century, from 1858 to 1947. Spanish viceroys ruled vast territories in Mexico, Peru, and other parts of the Americas for three centuries. These viceroys lived in grand palaces, held elaborate ceremonies, and essentially ran entire societies while the actual monarch remained thousands of miles away in Europe.
The viceroy system let empires control distant territories before telephones, airplanes, or even telegraphs existed. A message from London to India could take months by ship, so viceroys needed the authority to make important decisions on their own. This arrangement worked for the empire, though the people being governed by foreign viceroys often had very different feelings about it.