Queen mother in the context of "Helen of Greece and Denmark"

Queen of Heaven (Latin: Regina Caeli) is a title given by the Catholic Church and Eastern Orthodoxy, to Mary, mother of Jesus, and, to a lesser extent, in Evangelical Lutheranism and Anglicanism. The title has long been a tradition, included in prayers and devotional literature and seen in Western art in the subject of the Coronation of the Virgin from the High Middle Ages, long before the Church gave it a formal definition status.

The Catholic teaching on this subject is expressed in the papal encyclical Ad Caeli Reginam, issued by Pope Pius XII in 1954. Therein, the pope states that Mary is called Queen of Heaven because her son, Jesus Christ, was charged as being "King of Israel" and the heavenly king of the universe. This would render the mother of the king as the "queen mother" of Israel.

Frederica of Hanover (German: Friederike Luise; Greek: Φρειδερίκη Λουΐζα, romanized: Phreideríkē Louḯza; 18 April 1917 – 6 February 1981) was Queen of Greece from 1 April 1947 until 6 March 1964 as the wife of King Paul and the Queen Mother of Greece from 6 March 1964, when her son Constantine II became King, until 8 December 1974, when the monarchy was officially abolished after a referendum.

Granddaughter of Kaiser Wilhelm II and daughter of Duke Ernest Augustus of Brunswick, Frederica was born a few months before the fall of the German Empire. Her family overthrown, she grew up between Austria and Weimar Germany, where her father owned large properties. As a teenager, she joined the Hitler Youth in 1933, before leaving to complete her studies for the next two years in the United Kingdom and then Italy. In Florence, she was received by Princess Helen of Greece and Denmark, at whose house she met the Crown Prince of Greece, Paul. The two fell in love and married two years after the restoration of the monarchy in Greece. In the years that followed, she gave birth to three children, Sophia in 1938, Constantine in 1940 and Irene in 1942.

A queen dowager or dowager queen (compare: princess dowager or dowager princess) is a title or status generally held by the widow of a king. In the case of the widow of an emperor, the title of empress dowager is used. Its full meaning is clear from the two words from which it is composed: queen indicates someone who served as queen consort (i.e. wife of a king), while dowager indicates a woman who continues to hold the title from her deceased husband (a queen who reigns in her own right is a queen regnant). A queen mother is a former queen consort, often a dowager queen, who is the mother of the reigning monarch.

As of 2025, there are three queens dowager: Kesang Choden of Bhutan (who is the only living queen grandmother worldwide), Norodom Monineath of Cambodia (who is also queen mother), and Lisa Najeeb Halaby (Noor Al'Hussein) of Jordan.

Louisa Ulrika of Prussia (Swedish: Lovisa Ulrika; German: Luise Ulrike; 24 July 1720 - 16 July 1782) was Queen of Sweden from 1751 to 1771. She was married to king Adolf Frederick and she was queen mother during the reign of king Gustav III.