Head of State
The Head of State is the individual who is designated the most senior leader of a nation and who represents the national leadership in constitutional and international relations.
Heads of State fall into a number of categories. They can be elected or nominated Presidents, unelected monarchs, and elected Popes. In addition, while some heads of state do wield considerable executive power (such as the Presidents of the United States and France), others have more limited powers and serve mainly as a figurehead (such as the Presidents of Germany and Ireland). Most monarchies in the world today are constitutional monarchies, where the monarch has only symbolic powers and serves as an apolitical figurehead.
The world's longest serving Head of State is Queen Elizabeth II of the United Kingdom and a number of other Commonwealth countries, who succeeded to the Crown in 1952.