Alexandrine of Mecklenburg-Schwerin (24 December 1879 – 28 December 1952) was Queen of Denmark as the spouse of King Christian X.
 She was also Queen of Iceland from 1 December 1918 to 17 June 1944.
A referendum on changing the Danish Act of Succession, the rules governing the succession to the Danish throne, was held in Denmark, the Faroe Islands, and Greenland on 7 June 2009, simultaneously with the election to the European Parliament, in Denmark proper.
Sen Soulintha, Saen Surintha or Sen Sourintha (1511–1582) was born Chane Tian and became King of Lan Xang reigning 1571-1575 and again 1580-1582.
 Sen Soulintha was not of noble birth, rising from royal page to King Setthatirath’s Chief Minister.
 During the succession disputes in the Kingdom of Lan Na between King Setthatirath and King Mekuti, Sen Soulintha served Setthatirath as a general and successfully took several cities of Lan Na including Chiang Saen for which he was given the honorific name "Lusai" meaning “victory.”
 Sen Soulintha supported Setthatirath in leading the guerrilla campaigns during the Burmese invasions of King Bayinnaung.
 When Setthatirath died near Attapeu under suspicious circumstances in 1572, Sen Soulintha led the armies of Lan Xang back to Vientiane.
 A succession dispute erupted, which nearly led to civil war and provided a pretext for another Burmese invasion ordered by Bayinnaung and led by the Chief Minister Binnya Dala.
 Sen Soulintha defeated the Burmese and Lan Na forces led by Binnya Dala, an event which led to the latter’s exile, only to face a more massive invasion led by Bayinnaug the following year.
 Sen Soulintha again attempted to resort to guerilla tactics, but lacked popular support from his seizure of the throne.
 He and his son Ong Lo (Nakhon Noi) were captured by Bayinnaung and exiled to Pegu.
 The Burmese placed Setthathirath’s brother, and former "Ouphahat" or Viceroy, Prince Tha Heua on the throne.
 According to the Luang Prabang chronicles it was this brother, who had led a rebellion in Luang Prabang and tried to seize the throne from Setthathirath on the death of their father Photisarath.
 Prince Tha Heua took the regnal name Voravongsa and reigned under Burmese suzerainty from 1575-1579.
 Voravongsa was never popular, and drowned with his family while attempting to flee Vientiane in the face of popular uprising.
 In 1579, Bayinnaung dispatched a sizable army to restore order.
 According to Lao histories Sen Soulintha was then installed as king a second time in 1580.
 By that time Sen Soulintha was an old man and reigned only for two years before his son ascended the throne as Nakhon Noi and another succession dispute ensued.
Margrethe II (Danish: "Margrethe 2."
 , ] ; Faroese: "Margreta 2."
 ; Greenlandic: "Margrethe II" ; full name: "Margrethe Alexandrine Þórhildur Ingrid"; born 16 April 1940) is the Queen of Denmark.
 She is also the supreme authority of the Church of Denmark and Commander-in-Chief of the Danish Defence.
 Born into the House of Glücksburg, a royal house with origins in Northern Germany, she was the eldest child of Frederick IX of Denmark and Ingrid of Sweden.
 She succeeded her father upon his death on 14 January 1972, having had become heir presumptive to her father in 1953, when a constitutional amendment allowed women to inherit the throne.
 On her accession, Margrethe became the first female monarch of Denmark since Margaret I, ruler of the Scandinavian kingdoms in 1375–1412 during the Kalmar Union.
 In 1967, she married Henri de Laborde de Monpezat, with whom she has two sons: Crown Prince Frederik (born 1968) and Prince Joachim (born 1969).
 She has been on the Danish throne for 45 years, becoming the second-longest-reigning Danish monarch after her ancestor Christian IV.
The Danish Act of Succession, adopted on 27 March 1953, restricts the throne to those descended from Christian X and his wife, Alexandrine of Mecklenburg-Schwerin, through approved marriages.
 Succession is governed by absolute primogeniture.
The Succession to the Throne Act, 2013, which has the long title An Act to assent to alterations in the law touching the Succession to the Throne (Bill C-53), was passed by the Parliament of Canada to give assent to the Succession to the Crown Bill, which was intended to change the line of succession to the Canadian throne and was passed with amendments by the UK parliament on 25 April 2013.
 Bill C-53 was presented and received its first reading in the House of Commons on 31 January 2013 and received Royal Assent on 27 March of the same year.
 The act was brought into force by the Governor General-in-Council on 26 March 2015.
Prince Joachim of Denmark, Count of Monpezat, {'1': ", '2': ", '3': 'RE, SKmd', '4': "} (] ; Joachim Holger Waldemar Christian; born 7 June 1969 at Rigshospitalet in Copenhagen) is the younger son of Queen Margrethe II and Prince Henrik.
 Joachim is sixth in the line of succession to the Danish throne, following his elder brother, Crown Prince Frederik, and Frederik's four children.
Princess Eleonore-Christine of Schaumburg-Lippe (Eleonore-Christine Eugenie Benita Feodora Maria; born 22 December 1978 at Hørsholm, Denmark) is the daughter of Prince Waldemar of Schaumburg-Lippe and his first wife, Anne-Lise Johansen.
 Princess Eleonore-Christine is a great-great-granddaughter of King Frederick VIII of Denmark.
 Under Danish law, she is barred from succession to the Danish throne, as she is not a descendant of Christian X.
 However, through her father, she is a descendant of King George II of Great Britain, and is therefore in line for the British throne.
The Danish Act of Succession of 27 March 1953 was accepted after a 1953 referendum in Denmark and dictates the rules governing the line of succession to the Danish throne.
 The 1953 referendum changed the act so that it became possible for a woman to inherit the throne in the event that she has no older or younger brothers, a system known as male-preference cognatic preference primogeniture.
 As the reigning King Frederick IX had three daughters and no sons, this meant that Princess Margrethe became the heir presumptive instead of her uncle Prince Knud.
 As Frederick IX's wife Ingrid of Sweden was not expected to (and in fact did not) have any more children, this effectively ensured that Princess Margrethe would become Queen of Denmark, which she did.
Prince Nikolai of Denmark, Count of Monpezat (Nikolai William Alexander Frederik; born 28 August 1999), is a member of the Danish Royal Family.
 He is the elder son of Prince Joachim and his first wife, Alexandra, Countess of Frederiksborg.
 s of 2016 , Prince Nikolai is seventh in the line of succession to the Danish throne.
 At the time of his birth, he was third, after his uncle and father.

Question: The Succession to the Danish throne restricts the throne to who?
Answer: Alexandrine of Mecklenburg-Schwerin