In the feudal and aristocratic systems that dominated Europe for centuries, the monarch—typically a king or queen (less often a prince, princess, grand duke, or emperor)—stood at the apex of the noble hierarchy.
Absolute monarchs (Louis XIV, Peter the Great) wielded near-total control. Constitutional monarchs (post-1688 England, post-1815 Europe) shared power with parliaments. In elective monarchies (Holy Roman Empire, Poland-Lithuania), the monarch's authority was negotiated.
The monarch headed both the royal family (dynastic interests, marriages, succession) and the state (administration, justice, defense). These roles often intertwined—dynastic marriages sealed treaties; succession wars redrew maps.
By the 20th century, most European monarchies became constitutional or were abolished. Today, remaining monarchs (e.g., UK, Spain, Sweden, Norway, Netherlands, Belgium) are ceremonial heads of state with no governing power.