Question:  Prince George William of Great Britain is the son of the King of Great Britain who started his reign on what date?

Context articles: George II of Great Britain
George III of the United Kingdom
Royal Photographic Society
George William, Duke of Brunswick-Lüneburg
Prince George William of Great Britain
Earl Talbot
Tory government, 1783–1801
Monarchy of Ireland
Treaties of Reichenbach (1813)
Earl Harcourt

George II (George Augustus; German: "Georg II.
 August" ; 30 October / 9 November 1683  – 25 October 1760) was King of Great Britain and Ireland, Duke of Brunswick-Lüneburg (Hanover) and Prince-elector of the Holy Roman Empire from 11 June 1727 (O.S.) until his death.
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.
The Royal Photographic Society of Great Britain, commonly known as the Royal Photographic Society (RPS), is one of the world's oldest photographic societies.
 It was founded in London, England in 1853 as The Photographic Society of London with the objective of promoting the art and science of photography, and in 1854 received Royal patronage from Queen Victoria and Prince Albert.
 A change to the society's name to reflect the Royal patronage was, however, not considered expedient at the time.
 In 1874 it was renamed the Photographic Society of Great Britain, and from 1894 it became known as The Royal Photographic Society of Great Britain.
 A registered charity since 1962, in July 2004, The Royal Photographic Society of Great Britain was granted a Royal charter recognising its eminence in the field of photography as a learned society.
 For most of its history the Society was based at various premises in London.
 It moved to Bath in 1979, and since 2004 its headquarters has been at Fenton House in Bath, England.
 Membership is international and open to anyone with an interest in photography.
George William German: "Georg Wilhelm" (Herzberg am Harz, 26 January 1624 – 28 August 1705, Wienhausen) was Duke of Brunswick-Lüneburg.
 He ruled first over the Principality of Calenberg, a subdivision of the duchy, then over the Lüneburg subdivision.
 In 1689, he occupied the Duchy of Saxe-Lauenburg and passed it on to his successors.
 George William was the father of Sophia Dorothea of Celle, wife of George I of Great Britain.
Prince George William of Great Britain (13 November 1717 – 17 February 1718) was an infant member of the British royal family, second son of George II and Caroline of Ansbach who, at the time of his birth, were the Prince and Princess of Wales.
 He died aged 3 months, 4 days.
Earl Talbot is a title that has been created twice in the Peerage of Great Britain.
 This branch of the Talbot family descends from the Hon. Sir Gilbert Talbot (died 1518), third son of John Talbot, 2nd Earl of Shrewsbury.
 His great-great-great-grandson the Right Reverend William Talbot was Bishop of Oxford, of Salisbury and of Durham.
 His eldest son Charles Talbot was a prominent lawyer and politician.
 In 1733 he was raised to the Peerage of Great Britain as Lord Talbot, Baron of Hensol, in the County of Glamorgan, and then served as Lord Chancellor of Great Britain from 1733 to 1737.
 He was succeeded by his eldest son, the second Baron.
 He served as Lord Steward of the Household from 1761 to 1782.
 In 1761 he was created Earl Talbot and in 1780 Baron Dynevor, of Dynevor in the County of Carmarthen, in the Peerage of Great Britain.
 The earldom was created with normal remainder to the heirs male of his body while the barony was created with remainder to his daughter Cecil, wife of George Rice, and her issue male.
Tory William Pitt the Younger led the government of the Kingdom of Great Britain from 1783 to 1801.
 In 1800, the Acts of Union between Great Britain and Ireland were accepted by their respective parliaments, creating the new United Kingdom of Great Britain and Ireland, which would be governed by the former Parliament of Great Britain, now the Parliament of the United Kingdom.
 Pitt governed this new state for the first month of its existence, until differences with King George III over Catholic Emancipation caused him to resign.
A monarchical system of government existed in Ireland from ancient times until, for what became the Republic of Ireland, the mid-twentieth century.
 Northern Ireland, as part of the United Kingdom, remains under a monarchical system of government.
 The Gaelic kingdoms of Ireland ended with the Norman invasion of Ireland, when the kingdom became a fief of the Holy See under the Lordship of the King of England.
 This lasted until the Parliament of Ireland conferred the crown of Ireland upon King Henry VIII of England during the English Reformation.
 The monarch of England held the crowns of England and Ireland in a personal union.
 The Union of the Crowns in 1603 expanded the personal union to include Scotland.
 The personal union between England and Scotland became a political union with the enactments of the Acts of Union 1707, which created the Kingdom of Great Britain.
 The crowns of Great Britain and Ireland remained in personal union until it was ended by the Acts of Union 1800, which united Ireland and Great Britain into the United Kingdom of Great Britain and Ireland from January 1801 until December 1922.
The Treaties of Reichenbach were a series of agreements signed in Reichenbach (present-day Dzierżoniów) between Great Britain, Prussia, Russia, and Austria.
 These accords served to establish and strengthen a united coalition force against Napoleon I of France.
 On 14 June 1813 the Treaty of Reichenbach was signed between Great Britain and Prussia.
 Based on the terms of the accord, Britain agreed to provide Prussia a subsidy of 666,666 pounds sterling in order for Prussia to maintain its force of 80,000 troops.
 In exchange for this aid, the king of Prussia agreed to cede the principality of Hildesheim and other territories to the Electorate of Hanover.
 On 15 June 1813 the Treaty of Reichenbach was signed between Great Britain and Russia.
 Based on the terms of the accord, Great Britain agreed to provide Russia with a subsidy of 1,333,334 pounds sterling in order for Russia to maintain its force of 160,000 troops.
 On 27 June 1813 the Treaty of Reichenbach (also known as the "Reichenbach Convention") was signed between Prussia, Russia, and Austria.
 Based on the terms of the accord, Austria agreed to declare war against Napoleon if he rejected its conditions of peace.
Earl Harcourt, of Stanton Harcourt in the County of Oxford, was a title in the Peerage of Great Britain.
 It was created in 1749 for Simon Harcourt, 2nd Viscount Harcourt.
 He was made Viscount Nuneham at the same time, also in the Peerage of Great Britain.
 Harcourt was the son of the Honourable Simon Harcourt and the grandson of Simon Harcourt, Lord Chancellor of Great Britain, who had been created Baron Harcourt, of Stanton Harcourt in the County of Oxford, in 1711, and Viscount Harcourt, of Stanton Harcourt in the County of Oxford, in 1721.
 Both these titles were also in the Peerage of Great Britain.
 Two of the first Earl's sons, George, the second Earl, and William, the third Earl, both succeeded in the titles.
 The peerages became extinct on the latter's death in 1830.