Question: Augustus d'Este was the grandson of a monarch who was promoted to King of Hanover in what year?
Context: Concorso d'Eleganza Villa d'Este (Competition of Elegance of Villa d'Este) is an elegance competition for classic and vintage cars.  It has taken place every year since 1929 during the last weekend of April in Villa d'Este on the shores of Lake Como, Italy.  Since 2011 the event takes place in the second half of May. Sir Augustus Frederick d'Este, (13 January 1794 – 28 December 1848) was the son of Prince Augustus Frederick, Duke of Sussex, and Lady Augusta Murray, and a grandson of King George III.  His parents were secretly married on 4 April 1793, in a Church of England ceremony in the Hotel Sarmiento, Rome, and later married again on 5 December 1793 at St George's, Hanover Square, Westminster, using their correct names but without revealing their identities.  Both marriages were in defiance of the Royal Marriages Act 1772 and were thus legally null and void, at least in English law.  After the birth of their first child, the marriage was discovered by the King and formally annulled, making their son illegitimate in Great Britain. 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. Ernest Augustus (Ernest Augustus Christian George; German: "Ernst August Christian Georg" ; 17 November 1887 – 30 January 1953), reigning Duke of Brunswick (2 November 1913 – 8 November 1918), was a grandson of George V of Hanover, whom the Prussians deposed in 1866, and Christian IX of Denmark. 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: 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. Johann Reinhold Patkul (27 July 1660 – 10 October 1707) was a Livonian nobleman, politician and agitator of Baltic German extraction.  Born as a subject to the Swedish Crown, he protested against the manner of King Charles XI of Sweden's reduction in Livonia, enraging the king, who had him arrested and sentenced to mutilation and death (1694).  Patkul fled from the Swedish Empire to continental Europe, and played a key role in the secret diplomacy (1698-1699) allying Peter I of Russia, Augustus II the Strong of Saxony and the Poland–Lithuania - as well as Christian V and his successor Frederick IV of Denmark–Norway - against Charles XII of Sweden, triggering the Great Northern War of 1700-1721.  During the first war years, Patkul retained a key role in the communication between the allies and other European courts, holding positions at king Augustus's court first in Augustus's interests (1698-1700), then in tsar Peter's service (1702- ).  In late 1705 Patkul fell from Augustus's favor and was arrested and charged with high treason.  Throughout the following year he was detained first in Sonnenstein, then in Königstein (both in Saxony), before Charles XII forced Augustus to extradite him by the Treaty of Altranstädt in late 1706.  Patkul spent another year in Swedish detention before Charles XII had him broken on the wheel and decapitated. Ernst August, Hereditary Prince of Brunswick, Prince of Hanover (German: "Ernst August Prinz von Hannover" ; 18 March 1914 – 9 December 1987) was head of the House of Hanover from 1953 until his death.  He was born at Braunschweig, Germany, the eldest son of Ernest Augustus, Duke of Brunswick and Princess Viktoria Luise of Prussia, the only daughter of Emperor Wilhelm II, Ernest Augustus's third cousin in descent from George III of the United Kingdom.  Ernst August's parents were, therefore, third cousins, once removed.  From his birth, he was the "Hereditary Prince of Brunswick".  He was also, shortly after birth in 1914, made a British prince by King George V of the United Kingdom, and was heir to the titles Duke of Cumberland and Teviotdale and Earl of Armagh which were suspended under the Titles Deprivation Act 1917. Bernardino II da Polenta was lord of Ravenna, Italy from 1389 to 1400.  He was the son of Guido III da Polenta, grandson of Bernardino I and a member of the da Polenta family.  Bernardino's mother was Elisa d'Este, the daughter of Obizzo III d'Este of Ferrara, who gave him numerous children.  In 1389, Bernardino and his brothers, Ostasio, Obizzo, Aldobrandino, Azzo and Pietro imprisoned their father and ruled Ravenna.  The brothers died in quick succession; allegedly Bernardino was poisoned by his brother Obizzo. Emperor Frederick III elevated the Italian family of Este, Lords of Ferrara, to Dukes of Modena and Reggio in 1452, and Dukes of Ferrara in 1471.  In 1597, they lost the succession of Ferrara itself to the Papal States.  They continued to rule the Duchy of Modena and Reggio in the Emilia until 1796, when it became part of Napoleon Bonaparte's Cispadane Republic.  In 1814 the duchy was restored under the Habsburg grandson of the last Este Duke, continuing until annexed by Piedmont-Sardinia in 1859.
Answer: 1814