Question: James Stanier Clarke was the librarian to which King of Hanover?

Context paragraphs:
James Louis Gillis: James Louis Gillis (October 3, 1857 – July 27, 1917) was an American librarian.  Although Gillis was born in Richmond, Iowa, by the time he was 14 his family had settled in Sacramento, California.  At that time, Gillis had dropped out of school to become a messenger boy for a subsidiary for the Southern Pacific called the Sacramento Valley Railroad Company.  After the Pullman railroad strike Gillis retired from his position of assistant superintendent after 22 years with Southern Pacific.  At the end of his railroad career he was extremely active with the Republican party, and because of connections he made politically, James Gillis became the archivist for the Office of the Secretary of State in 1895.  After a series of state positions Gillis was appointed California State Librarian in 1899.  Though most of his previous work experience didn’t include library topics, Gillis was nonetheless attracted to the job.  Librarian Anne Margrave stated,

George IV of the United Kingdom: George IV (George Augustus Frederick; 12 August 1762 – 26 June 1830) was King of the United Kingdom of Great Britain and Ireland and of Hanover following the death of his father, George III, on 29 January 1820, until his own death ten years later.  From 1811 until his accession, he served as Prince Regent during his father's final mental illness.

James Stanier Clarke: James Stanier Clarke (1766–1834) was an English cleric, naval author and man of letters.  He became librarian in 1799 to George, Prince of Wales (later Prince Regent, then George IV).

List of Hanoverian consorts: Consorts of Hanover were women married to the Hanoverian monarchs during their reigns.  Because of the salic law of succession, all monarchs of Hanover were male with the title of King of Hanover and before that Elector of Hanover, while all Hanoverian consorts were women with the title of Queen of Hanover and style Majesty and before that title Electress of Hanover and style Royal Highness.  The following women spouses of the monarchs of Hanover between 1692 and 1878:

Ernest Augustus, King of Hanover: Ernest Augustus (5 June 1771 – 18 November 1851) was King of Hanover from 20 June 1837 until his death.  He was the fifth son and eighth child of King George III of the United Kingdom and Hanover.  As a fifth son, Ernest seemed unlikely to become a monarch, but none of his four elder brothers had a legitimate son who survived infancy.  The Salic Law, which barred succession to or through a female, prevailed in Hanover; therefore, when his elder brother King William IV died in 1837, Ernest succeeded him as King of Hanover.  In the United Kingdom the succession to the monarchy was determined by primogeniture and his niece Victoria succeeded to the throne, thus ending the personal union between the British Isles and Hanover that had existed since 1714.

Milton J. Ferguson: Milton James Ferguson (April 11, 1879 – October 23, 1954) was an American librarian.  He graduated from the University of Oklahoma in 1906, and served as librarian of the University of Oklahoma from 1902 to 1907.  He helped organize and was elected the first President of the Oklahoma Library Association (1907–08).  He later became California State Librarian (1917–1930).  In 1926 Ferguson was an honorary member of the California Society of Printmakers (né Etchers).  He worked for the Carnegie Corporation making library surveys in Africa, and was librarian of the Brooklyn Public Library until 1949.  In 1938–39, Ferguson was president of the American Library Association.

The Librarian: Return to King Solomon's Mines: The Librarian: Return to King Solomon's Mines is the second in "The Librarian" franchise of movies starring Noah Wyle as a librarian who protects a secret collection of artifacts.  Gabrielle Anwar, Bob Newhart, Jane Curtin and Olympia Dukakis co-star.  It is a sequel to 2004's "".  The third film in the trilogy, "", was released in 2008.

James H. Billington: James Hadley Billington (born June 1, 1929), the Librarian of Congress Emeritus, is a leading American academic and author who taught history at Harvard and Princeton before serving for 42 years as CEO of four federal cultural institutions.  He served as the 13th Librarian of Congress after being nominated as 13th by President Ronald Reagan in 1987, and his appointment was approved unanimously by the U.S. Senate.  He retired as Librarian on September 30, 2015.

Bodley's Librarian: The head of the Bodleian Library, the main library at the University of Oxford, is known as Bodley's Librarian: Sir Thomas Bodley, as founder, gave his name to both the institution and the position.  Although there had been a university library at Oxford since about 1320, it had declined by the end of the 16th century.  It was "denuded" of its books in 1550 in the time of King Edward VI when "superstitious books and images" that did not comply with the prevailing Anglican view were removed.  Poor management and inadequate financial resources have also been blamed for the state of the library.  In the words of one history of the university, "as a public institution, the Library had ceased to function."  Bodley volunteered in 1598 to restore it; the university accepted the offer, and work began soon thereafter.  The first librarian, Thomas James, was selected by Bodley in 1599.  The Bodleian opened in 1602, and the university confirmed James in his post.  Bodley wanted the librarian to be "some one that is noted and known for a diligent student, and in all his conversation to be trusty, active, and discrete, a graduate also and a linguist, not encumbered with marriage, nor with a benefice of Cure" (i.e. not a parish priest).  James, however, was able to persuade Bodley to let him marry and become Rector of St Aldate's Church, Oxford.

George III of the United Kingdom: George III (George William Frederick; 4 June 1738 – 29 January 1820) was King of Great Britain and Ireland from 25 October 1760 until the union of the two countries on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death.  He was concurrently Duke and prince-elector of Brunswick-Lüneburg ("Hanover") in the Holy Roman Empire until his promotion to King of Hanover on 12 October 1814.  He was the third British monarch of the House of Hanover, but unlike his two predecessors, he was born in Britain, spoke English as his first language, and never visited Hanover.

Supporting paragraphs: James Stanier Clarke George IV of the United Kingdom
Answer: George IV