A queen regnant is a female monarch, equivalent in rank, title and position to a king. She reigns suo jure over a realm known as a kingdom; as opposed to a queen consort, who is married to a reigning king; or a queen regent, who is the guardian of a child monarch and rules pro tempore in the child's stead or instead of her husband who is absent from the realm, be it de jure in sharing power or de facto in ruling alone. A queen regnant is sometimes called a woman king. A princess regnant is a female monarch who reigns suo jure over a principality; an empress regnant is a female monarch who reigns suo jure over an empire.
Queen Elizabeth II, who reigned as queen of the United Kingdom from 1952 until her death in 2022, is the longest-reigning queen regnant in world history.
Bust of Sobekneferu, the earliest Pharaoh of Egypt confidently proven to have been a woman (r. 18th/17th century BC)
Margaret I ruled Denmark, Norway and Sweden in the late 14th and early 15th centuries.
A monarch is a head of state for life or until abdication, and therefore the head of state of a monarchy. A monarch may exercise the highest authority and power in the state, or others may wield that power on behalf of the monarch. Usually a monarch either personally inherits the lawful right to exercise the state's sovereign rights or is selected by an established process from a family or cohort eligible to provide the nation's monarch. Alternatively, an individual may proclaim oneself monarch, which may be backed and legitimated through acclamation, right of conquest or a combination of means.
The Nine Sovereigns at Windsor for the funeral of King Edward VII, photographed on 20 May 1910. Standing, from left to right: King Haakon VII of Norway, Tsar (King) Ferdinand of the Bulgarians, King Manuel II of Portugal and the Algarve, Kaiser (Emperor) Wilhelm II of Germany, King George I of the Hellenes and King Albert I of the Belgians. Seated, from left to right: King Alfonso XIII of Spain, King George V of the United Kingdom and King Frederik VIII of Denmark.
Postcard from 1908 showing nineteen of the world's reigning monarchs: (left to right)King Rama V/Chulalongkorn of Siam (modern Thailand), King George I of Greece, King Peter I of Serbia, King Carol I of Romania, Emperor and King Franz Joseph of Austria-Hungary, Tzar (King) Ferdinand I of Bulgaria, Padishah (Emperor) Abdul Hamid II of the Ottoman Empire, King Victor Emmanuel III of Italy, Emperor Nicholas II of the Russia, King Edward VII of the United Kingdom,
Ramesses II (r. 1279–1213 BC), the third Pharaoh of the Nineteenth Dynasty of Egypt
Mohamoud Ali Shire, the 26th Sultan of the Somali Warsangali Sultanate